78 + Interview Questions in Motion In A Plane in Physics

1.	A body of weight 20 N, mass 2 kg is moving in vertical circular motion with the help of a string of radius 1 m and with a velocity of 2 m/s. What is the tension in the string at the lowest point?(a) 28 N(b) 20 N(c) 8 N(d) 15 NThe question was posed to me during an internship interview.This intriguing question originated from Uniform Circular Motion in section Motion in a Plane of Physics – Class 11
Answer» Right OPTION is (a) 28 N To elaborate: At the lowest point, the body experiences centrifugal force and the weight in the same direction, opposite to the direction of TENSION in the string. Centrifugal force can be calculated as mv^2/r = 8 N. Hence the tension = weight + centrifugal force = 28 N.

Discussion

2.	The angular velocity of a stone being rotated is 11 rad/s. What is the angular displacement covered in 0.5s?(a) 5.5 rad(b) 0.55 rad(c) 55 rad(d) 0.5 radThe question was posed to me in my homework.Question is taken from Uniform Circular Motion in chapter Motion in a Plane of Physics – Class 11
Answer» RIGHT answer is (a) 5.5 rad To elaborate: Angular velocity is the RATE of change of angular DISPLACEMENT. Here the angular velocity is 11 rad/s. This implies that in one second the stone rotates by an ANGLE of 11 rad. Hence in 0.5 s it will cover an angular displacement if 5.5 rad.

Discussion

3.	The centrifugal force always acts _____(a) Towards the center(b) Away from the center(c) In tangential direction(d) Outside of the plane of motionI got this question in an interview.My query is from Uniform Circular Motion topic in portion Motion in a Plane of Physics – Class 11
Answer» Correct option is (b) AWAY from the center The EXPLANATION is: The centrifugal force always acts away from the center of the circle in which the BODY is moving. In CONTRAST to this, the centripetal force always acts towards the center of the circle, keeping the body moving in the circle.

Discussion

4.	A bag of mass 1000 g, projected at an angle of 90° from the ground with an initial velocity of 5 m/s, acceleration due to gravity is g = 10 m/s^2, what is the maximum height attained?(a) 1.25 m(b) 3.0 m(c) 1.5 m(d) 2.0 mThe question was asked in class test.This question is from Simple Projectile Motion in chapter Motion in a Plane of Physics – Class 11
Answer» The correct option is (a) 1.25 m The BEST I can explain: The FORMULA for maximum height is H = (v sinθ)^2/2g. Here, v = 5, θ = 90°, g = 10. Hence, on solving we will get the maximum height attained as 1.25 m. The maximum height can alternatively be found by simply using equations of MOTION as this bag is thrown vertically UPWARDS.

Discussion

5.	A body is moving with a constant acceleration of 4î + 3&jcirc;, starting from the origin. What will be the position of the body after 5s?(a) 50î + 37.5&jcirc;(b) 37.5î + 50&jcirc;(c) 37.5î –50&jcirc;(d) 50î – 37.5&jcirc;I got this question during a job interview.The above asked question is from Motion in a Plane topic in section Motion in a Plane of Physics – Class 11
Answer» The CORRECT answer is (a) 50î + 37.5&jcirc; Explanation: The body’s displacement is given by s = (1/2)at^2. The body starts from the origin hence, the TOTAL displacement is the final position of the body. THEREFORE, after putting in the values, we GET, s = (1/2)(4î + 3&jcirc;)*5^2 = 50î + 37.5&jcirc;.

Discussion

6.	Velocity of a man is 25 units in the positive X direction and 75 units in negative Y direction starting from the origin. Velocity of a woman is 25 units in the positive Y direction and 75 units in the negative X direction starting from the origin. What is the relative velocity of the man with respect to the woman?(a) 100î – 100&jcirc;(b) 100î + 100&jcirc;(c) -100î – 100&jcirc;(d) 0î + 0&jcirc;I have been asked this question during an interview for a job.My question is taken from Motion in a Plane in section Motion in a Plane of Physics – Class 11
Answer» Correct choice is (a) 100î – 100&jcirc; The explanation: The VELOCITY of the man is 25î – 75&jcirc; and that of the WOMAN is -75î + 25&jcirc;. RELATIVE velocity = velocity of man – velocity of woman = 100î – 100&jcirc;.

Discussion

7.	Which of the following is not true about projectile motion?(a) It is an example of motion in a plane(b) It is an example of motion along a curve(c) It is not an example of motion in space(d) The acceleration keeps changing in projectile motionI have been asked this question during an internship interview.My question is based upon Motion in a Plane topic in portion Motion in a Plane of Physics – Class 11
Answer» The correct ANSWER is (a) It is an example of motion in a plane For explanation: The only ACCELERATION in projectile motion is the acceleration due to gravity. If the MAXIMUM height of the projectile motion is not LARGE, and can be neglected with respect to the radius of earth (which usually is the case), the acceleration due to gravity remains constant. Hence, the acceleration in projectile motion remains constant.

Discussion

8.	Which of the following is not an example of motion in a plane?(a) A car moving in a rectangular path(b) A bicycle moving in a circular path(c) A rocket moving into space(d) A truck moving in an infinite spiralThe question was asked in quiz.I want to ask this question from Motion in a Plane topic in portion Motion in a Plane of Physics – Class 11
Answer» Right CHOICE is (c) A rocket moving into space The best I can EXPLAIN: A rocket moving into space is an example of 3-dimensional motion. Hence, it cannot be out in the category of motion in a PLANE. Rest all examples of motion in a plane. The truck moving in an INFINITE spiral is also an example of motion in a plane as spiral is a 2-dimensional ENTITY.

Discussion

9.	A vector, 7 units from the origin, along the X axis, is added to vector 11 units from the origin along the Y axis. What is the resultant vector?(a) 3î + 8&jcirc;(b) 7î + 11&jcirc;(c) 11î + 7&jcirc;(d) 2î + 7&jcirc;This question was addressed to me in an international level competition.My doubt stems from Vector Addition in section Motion in a Plane of Physics – Class 11
Answer» Right option is (b) 7î + 11&jcirc; Explanation: The VECTOR 7 units from the ORIGIN and along X axis is 7î. The vector 11 units from the origin and along Y axis is 11&jcirc;. Hence the sum is 7î + 11&jcirc;.

Discussion

10.	At which position in vertical circular motion is the tension in the string minimum?(a) At the highest position(b) At the lowest position(c) When the string is horizontal(d) At an angle of 35° from the horizontalThis question was addressed to me in final exam.I'm obligated to ask this question of Uniform Circular Motion in section Motion in a Plane of Physics – Class 11
Answer» The CORRECT option is (a) At the HIGHEST position To ELABORATE: When the body is at the highest point of its motion. This is because at the highest point the TENSION = centrifugal force – weight. This is the minimum value for tension throughout the motion.

Discussion

11.	A body of mass 10 kg, projected at an angle of 30° from the ground with an initial velocity of 5 m/s, acceleration due to gravity is g = 10 m/s^2, what is the time of flight?(a) 0.866s(b) 1.86 s(c) 1.96 s(d) 1.862 sThe question was posed to me during an internship interview.Origin of the question is Simple Projectile Motion topic in chapter Motion in a Plane of Physics – Class 11
Answer» The correct choice is (a) 0.866s To EXPLAIN I WOULD say: The formula for time of flight is t = 2(v sinθ/G). Here, v = 5, θ = 30°, g = 10. Hence, on solving we will GET the time of flight as 0.866 s.

Discussion

12.	A soccer ball is projected at an angle of 60° from the ground.It attains its maximum height in 10s. Considering acceleration due to gravity as g = 10 m/s^2. What is the velocity with which it was projected?(a) 115.5 m/s(b) 117 m/s(c) 120 m/s(d) 11.55 m/sThis question was addressed to me in unit test.This intriguing question comes from Simple Projectile Motion topic in chapter Motion in a Plane of Physics – Class 11
Answer» The CORRECT option is (a) 115.5 m/s Explanation: The time for achieving the MAXIMUM height is EQUAL to half of the time of flight. Therefore, the time of flight is 20s. The formula for time of flight is t = 2(v sinθ/g). Here, t = 20, θ = 60°, g = 10. Hence, on SOLVING we will get the initial VELOCITY as 115.5m/s.

Discussion

13.	The velocity of a car A is to 5î + 11&jcirc;. The velocity of another car B is 11î + 5&jcirc;. What is the relative velocity of B with respect to A?(a) 6î – 6&jcirc;(b) 11î + 5&jcirc;(c) 6î + 6&jcirc;(d) 5î + 5&jcirc;I got this question in homework.My doubt is from Motion in a Plane topic in section Motion in a Plane of Physics – Class 11
Answer» The correct answer is (a) 6î – 6&JCIRC; EASIEST explanation: The formula for calculating relative velocity of a body with respect to another body is- relative velocity = Velocity VECTOR of A – Velocity vector of B. Hence, here, the relative velocity = velocity of B – velocity of A = 6î – 6&jcirc;.

Discussion

14.	A ball is being rotated in a circle of radius 5 m with a constant tangential velocity of 20 m/s. A stone is also being rotated in a circle of radius 4 m with a constant tangential velocity of 16 m/s. Which one of the following choices is true about both the circular motions?(a) Both have same angular velocity(b) Both have different angular velocity(c) Angular velocity of ball > angular velocity of stone(d) Angular velocity of stone > angular velocity of ballI got this question in unit test.This interesting question is from Uniform Circular Motion topic in division Motion in a Plane of Physics – Class 11
Answer» Correct choice is (a) Both have same ANGULAR velocity The best EXPLANATION: Angular velocity = Tangential velocity/Radius. When we put in the VALUES and calculate the angular velocities for each of the circular MOTIONS, we see that both the angular velocities are EQUAL to each other and the value is 4 rad/s.

Discussion

15.	A body of mass 10 kg, is moving with a velocity of 5 m/s in a circle of radius 5 m, what is the centripetal acceleration of the body?(a) 5m/s^2(b) 25m/s^2(c) 0.5 m/s^2(d) 50 m/s^2I have been asked this question by my college director while I was bunking the class.The doubt is from Uniform Circular Motion topic in chapter Motion in a Plane of Physics – Class 11
Answer» CORRECT option is (a) 5m/s^2 The BEST explanation: The formula for centripetal force is mv^2/r. HENCE the centripetal acceleration is given by v^2/r. Here, v = 5, r= 5. Hence, on solving we will GET the centripetal acceleration as 5m/s^2.

Discussion

16.	The mathematical expression for centripetal force is ______(a) mv^2/r(b) mv/r(c) v^2/r(d) mv^3/rThe question was posed to me in an internship interview.Origin of the question is Uniform Circular Motion topic in portion Motion in a Plane of Physics – Class 11
Answer» Right OPTION is (a) mv^2/r The best I can EXPLAIN: The centripetal force is directly proportional to the square of the tangential VELOCITY and INVERSELY to the radius of circle. Hence, on calculating, we get the expression as mv^2/r.

Discussion

17.	The force that keeps the body moving in circular motion is _______(a) Centripetal force(b) Centrifugal force(c) Force of gravity(d) Reaction forcesI have been asked this question in a national level competition.This key question is from Uniform Circular Motion topic in division Motion in a Plane of Physics – Class 11
Answer» The correct option is (a) Centripetal FORCE The best explanation: Centripetal force is RESPONSIBLE for keeping bodies moving in circular motion. The centripetal force is directly proportional to the SQUARE of the tangential velocity and inversely to the radius of CIRCLE.

Discussion

18.	A body of mass 55 kg, projected at an angle of 45° from the ground with an initial velocity of 15 m/s, acceleration due to gravity is g = 10 m/s^2, what is the maximum horizontal range covered?(a) 22.5 m(b) 25 m(c) 16 m(d) 15 mThe question was posed to me by my college professor while I was bunking the class.I'd like to ask this question from Simple Projectile Motion topic in division Motion in a Plane of Physics – Class 11
Answer» CORRECT answer is (a) 22.5 m Explanation: The formula for horizontal RANGE is R = v^2 (sin 2θ)/G. Here, v = 15, θ = 45°, g = 10. Hence, on SOLVING we will get range as 22.5 m.

Discussion

19.	A body of mass m, projected at an angle of θ from the ground with an initial velocity of v, acceleration due to gravity is g, what is the maximum horizontal range covered?(a) R = v^2 (sin 2θ)/g(b) R = v^2 (sin θ)/2g(c) R = v^2 (sin 2θ)/2g(d) R = v^2 (sin θ)/gI have been asked this question in a job interview.My question is based upon Simple Projectile Motion in chapter Motion in a Plane of Physics – Class 11
Answer» CORRECT choice is (a) R = v^2 (sin 2θ)/g Explanation: The calculation for range uses the horizontal COMPONENT of the initial velocity and time. Range = distance x Time taken for the MOTION. The time can be FOUND by utilising the fact that the vertical velocity becomes zero at the MAXIMUM height (i.e. at half of the time period) and using the first equation of motion for this. Hence, on calculating, the range will be obtained as R = v^2 (sin 2θ)/g.

Discussion

20.	A vector, 5 units from the origin, along the X axis, is added to vector 2 units from the origin along the Y axis. What is the resultant vector?(a) 3î + 8&jcirc;(b) 5î + 2&jcirc;(c) 2î + 5&jcirc;(d) 2î + 7&jcirc;This question was addressed to me during a job interview.The doubt is from Vector Addition in portion Motion in a Plane of Physics – Class 11
Answer» Right ANSWER is (b) 5î + 2&jcirc; Easiest explanation: The vector 5 units from the origin and ALONG X axis is 5î. The vector 2 units from the origin and along Y axis is 2&jcirc;. Hence the sum is 5î + 2&jcirc;.

Discussion

21.	Which one of the following devices acts on the principle of circular motion?(a) Centrifuge(b) Screw Gauge(c) Ruler(d) Vernier calipersI have been asked this question during an interview for a job.My question is from Uniform Circular Motion topic in chapter Motion in a Plane of Physics – Class 11
Answer» RIGHT answer is (a) CENTRIFUGE The best EXPLANATION: The centrifuge utilizes the centrifugal force produced during circular motion. Centrifuge is COMMONLY used to separate platelets from blood samples. It is an important EQUIPMENT for studying blood. Other variations of centrifuge include devices like cream separator etc.

Discussion

22.	A body is moving with a constant acceleration of 11î + 2&jcirc;, starting from î + &jcirc;. What will be the position of the body after 10s?(a) 551î + 101&jcirc;(b) 550î + 100&jcirc;(c) 100î – 550&jcirc;(d) 550î – 550&jcirc;I had been asked this question by my college director while I was bunking the class.I need to ask this question from Motion in a Plane in section Motion in a Plane of Physics – Class 11
Answer» Right choice is (a) 551î + 101&jcirc; To explain: The BODY’s DISPLACEMENT is given by s = (1/2)at^2. Therefore, after PUTTING in the values, we get, s = (1/2)(11î + 2&jcirc;)*10^2 = 550î + 100&jcirc;. The body initially STARTS from î + &jcirc;. Hence, the final POSITION is = initial position + displacement = 551î + 101&jcirc;.

Discussion

23.	A body is exhibiting circular motion. What kind of motion can this be termed as?(a) Motion along a line(b) Motion in a plane(c) Motion in space(d) Motion along a pointThis question was posed to me by my college professor while I was bunking the class.The above asked question is from Motion in a Plane in chapter Motion in a Plane of Physics – Class 11
Answer» The correct ANSWER is (B) Motion in a plane Best EXPLANATION: Circular motion is an example of motion in a plane. As a CIRCLE is a 2-dimensional entity, the body MOVING in a circle is also moving in a plane. Hence the motion can be termed as motion in a plane.

Discussion

24.	The position of a body, moving in a plane, changes from origin to 14î + 11&jcirc; in 20s. What is the velocity of the body?(a) 0.7î + 0.55&jcirc;(b) 0.55î + 0.7&jcirc;(c) 0.3î + 0.7&jcirc;(d) 0.3îI got this question in an internship interview.This intriguing question originated from Motion in a Plane with Constant Acceleration in section Motion in a Plane of Physics – Class 11
Answer» The correct choice is (a) 0.7î + 0.55&JCIRC; For explanation: The VELOCITY of a body is the rate at which the displacement CHANGES with time. Here, the change in POSITION is the change in displacement, and is 14î + 11&jcirc;. The total time taken is 20S. Hence, the acceleration = change in displacement/time = 0.7î + 0.55&jcirc;.

Discussion

25.	A body of mass 5 kg, projected at an angle of 45° from the ground covers a horizontal range of 45 m, acceleration due to gravity is g = 10 m/s^2, what is the velocity with which it was projected covered?(a) 21.21 m/s(b) 20 m/s(c) 22 m/s(d) 21.1 m/sThe question was asked in a national level competition.My doubt stems from Simple Projectile Motion topic in portion Motion in a Plane of Physics – Class 11
Answer» Correct ANSWER is (a) 21.21 m/s The best I can explain: The formula for horizontal range is R = v^2 (sin 2θ)/G. Here, R = 45, θ = 45°, g = 10. Hence, on solving we will get velocity as 21.21 m/s. The result can be cross checked by putting this value of velocity and finding out the range.

Discussion

26.	A ball of mass 100 g, projected at an angle of 30° from the ground with an initial velocity of 11 m/s, acceleration due to gravity is g = 10 m/s^2, what is the maximum height attained?(a) 1.5 m(b) 3.0 m(c) 1.0 m(d) 2.0 mThe question was posed to me by my school principal while I was bunking the class.This is a very interesting question from Simple Projectile Motion in chapter Motion in a Plane of Physics – Class 11
Answer» The correct choice is (a) 1.5 m The best explanation: The formula for maximum height is H = (V sinθ)^2/2g. Here, v = 11, θ = 30°, G = 10. Hence, on SOLVING we will get the maximum height attained as 1.5125 m. The value can be rounded off to 1.5.

Discussion

27.	The velocity of a car A is to 5î. The velocity of another car B is 22î – 7&jcirc;. What is the relative velocity of A with respect to B?(a) -17î + 7&jcirc;(b) 7î + 17&jcirc;(c) -7î + 17&jcirc;(d) -17î + 7&jcirc;I have been asked this question by my college director while I was bunking the class.The question is from Motion in a Plane topic in chapter Motion in a Plane of Physics – Class 11
Answer» Right choice is (a) -17î + 7&jcirc; To explain I would SAY: The FORMULA for calculating relative velocity of a body with respect to another body is- relative velocity = Velocity VECTOR of A – Velocity vector of B. Hence, here, the relative velocity = velocity of B – velocity of A = -17î + 7&jcirc;.

Discussion

28.	A body moves from point A (2,1) to point B (7,13) to point C (15,19). What is the average speed of the body along the given path if the total time taken is 20 s?(a) 1.15 units/s(b) 11.5 units/s(c) 115 units/s(d) 0.0115 units/sI had been asked this question by my college director while I was bunking the class.This interesting question is from Motion in a Plane with Constant Acceleration topic in section Motion in a Plane of Physics – Class 11
Answer» Right answer is (a) 1.15 UNITS/s For explanation I WOULD say: The DISTANCE between A and B is 13 units. The distance between B and C is 10 units. Hence, the total distance is 23 units. The total TIME taken is 20 s. Average speed = total distance/total time taken = 23/20 = 1.15 units/s.

Discussion

29.	A vector, 14 units from the origin, along the X axis, is added to vector 16 units from the origin along the Z axis. What is the resultant vector?(a) 3î + 8\(\hat{z}\)(b) 14î + 16\(\hat{z}\)(c) 16î + 14\(\hat{z}\)(d) 2î + 7\(\hat{z}\)The question was asked in quiz.My enquiry is from Vector Addition in division Motion in a Plane of Physics – Class 11
Answer» Right option is (b) 14î + 16\(\hat{z}\) Explanation: The VECTOR 14 UNITS from the ORIGIN and along X AXIS is 14î. The vector 16 units from the origin and along Y axis is 16\(\hat{z}\). Hence the SUM is 14î + 16\(\hat{z}\).

Discussion

30.	When do we get maximum height in a simple projectile motion?(a) When θ = 45°(b) When θ = 60°(c) When θ = 90°(d) When θ = 0°This question was addressed to me in an international level competition.Question is from Simple Projectile Motion in division Motion in a Plane of Physics – Class 11
Answer» The correct OPTION is (c) When θ = 90° For EXPLANATION: The formula for horizontal range is h = (V sinθ)^2/2g. This will be maximum when SIN θ = 1, which implies that θ = 90°. Hence the correct answer is when θ = 90°.

Discussion

31.	Unit vector which is perpendicular to the vector 4î + 3&jcirc; is _____(a) &jcirc;(b) î(c) 4î + 3&jcirc;(d) \(\hat{z}\)This question was addressed to me in an online quiz.This interesting question is from Vector Addition topic in chapter Motion in a Plane of Physics – Class 11
Answer» The correct OPTION is (d) \(\hat{z}\) Explanation: The dot product of any two vectors which are perpendicular to each other is 0. The dot product of all the vectors in the OPTIONS with 4î + 3&jcirc; is non-zero EXCEPT for \(\hat{z}\). Hence \(\hat{z}\) is perpendicular to the given VECTOR.

Discussion

32.	In how many independent directions can a vector in a plane be resolved?(a) 1(b) 2(c) 3(d) 4I have been asked this question at a job interview.Question is from Motion in a Plane topic in chapter Motion in a Plane of Physics – Class 11
Answer» RIGHT option is (B) 2 Easiest explanation: A vector in a PLANE will be defined by the TWO governing axes, X and Y. Hence, any vector can be RESOLVED in two independent directions. If it is resolved in any other direction, that component of it will be dependent on the existing independent directions.

Discussion

33.	A body is moving in a vertical circular motion. Which one of the following forces does it not experience?(a) Force of gravity(b) Centripetal force(c) Normal reaction force(d) Centrifugal forceI got this question in quiz.I'd like to ask this question from Uniform Circular Motion topic in section Motion in a Plane of Physics – Class 11
Answer» The correct choice is (c) NORMAL reaction force The explanation is: A body MOVING in VERTICAL circular motion experiences these four forces – centripetal force, centrifugal force, force of gravity, and resistance offered by the medium in which it is moving. APART from these, it does not experience any other force in normal conditions.

Discussion

34.	When do we get maximum range in a simple projectile motion?(a) When θ = 45°(b) When θ = 60°(c) When θ = 90°(d) When θ = 0°The question was posed to me during an internship interview.The doubt is from Simple Projectile Motion in chapter Motion in a Plane of Physics – Class 11
Answer» CORRECT option is (a) When θ = 45° Easiest EXPLANATION: The formula for horizontal range is R = v^2(sin 2θ)/G. This will be MAXIMUM when sin 2θ = 1, which implies that 2θ = 90°, which in turn implies that θ = 45°. Hence the correct answer is when θ = 45°.

Discussion

35.	Which of the following is an example of uniformly accelerated motion in a plane?(a) Motion of a particle in a plane(b) Motion of a particle in a circle(c) Motion of a pendulum(d) Motion of a springI got this question in my homework.Question is from Motion in a Plane with Constant Acceleration topic in chapter Motion in a Plane of Physics – Class 11
Answer» CORRECT choice is (a) MOTION of a particle in a plane For explanation: From the GIVEN options, the only motion that can possibly have a uniformly accelerated motion in a plane is that of a particle. In circular motion the direction of the acceleration keeps changing and in a pendulum and in a spring, both the MAGNITUDE and directions KEEP changing.

Discussion

36.	A body of mass 5 kg, projected at an angle of 60° from the ground with an initial velocity of 25 m/s, acceleration due to gravity is g = 10 m/s^2, what is the maximum horizontal range covered?(a) 54.13 m(b) 49 m(c) 49.16 m(d) 60 mI had been asked this question by my college director while I was bunking the class.I'd like to ask this question from Simple Projectile Motion topic in portion Motion in a Plane of Physics – Class 11
Answer» Correct choice is (a) 54.13 m Explanation: The formula for HORIZONTAL RANGE is R = V^2 (sin 2θ)/g. Here, v = 25, θ = 60°, g = 10. Hence, on solving we will get range as 54.13 m.

Discussion

37.	At what angle of projectile (θ) is the horizontal range minimum?(a) θ = 45°(b) θ = 60°(c) θ = 90°(d) θ = 75°The question was asked in quiz.The question is from Simple Projectile Motion topic in division Motion in a Plane of Physics – Class 11
Answer» Correct choice is (c) θ = 90° Explanation: The formula for horizontal range is R = v^2 (sin 2θ)/g. When θ = 90°, sin 2θ = sin 180° = 0. HENCE, the range covered BECOMES 0. Since range cannot be negative, 0 is the minimum VALUE it can attain.

Discussion

38.	Velocity of a dog is 15 units in the positive X direction and 3 units in positive Y direction starting from the origin. Velocity of a pig is 7 units in the positive Y direction and 17 units in the positive X direction starting from the origin. What is the relative velocity of the dog with respect to the pig?(a) -2î – 4&jcirc;(b) -3î – 2&jcirc;(c) -4î – 2&jcirc;(d) 7î + 4&jcirc;I had been asked this question in examination.Enquiry is from Motion in a Plane in section Motion in a Plane of Physics – Class 11
Answer» The correct choice is (a) -2î – 4&jcirc; To EXPLAIN: The VELOCITY of the MAN is 15î+3&jcirc; and that of the woman is 17î + 7&jcirc;. Relative velocity = velocity of dog– velocity of pig = -2î – 4&jcirc;.

Discussion

39.	The velocity of a body, moving in a plane, changes from 3î to 3î + 7&jcirc; in 10s. What is the acceleration of the body?(a) 0.7&jcirc;(b) 0.7î(c) 0.33î + 7&jcirc;(d) 0.3î + 7&jcirc;The question was asked in an interview for internship.My question comes from Motion in a Plane with Constant Acceleration topic in portion Motion in a Plane of Physics – Class 11
Answer» The CORRECT answer is (a) 0.7&jcirc; To EXPLAIN I would say: The acceleration of a body is the RATE at which the VELOCITY changes with time. Here, the CHANGE in velocity is 7&jcirc;. The total time taken is 10s. Hence, the acceleration = change in velocity/time = 0.7&jcirc;.

Discussion

40.	A big stone of mass 1000 g, projected at an angle of 30° from the ground it covers a maximum vertical distance of 5 m, acceleration due to gravity is g = 10 m/s^2, what is the velocity with which it was thrown?(a) 11.55 m/s(b) 11.5 m/s(c) 1.155 m/s(d) 12.0 m/sThe question was asked by my school teacher while I was bunking the class.This is a very interesting question from Simple Projectile Motion topic in portion Motion in a Plane of Physics – Class 11
Answer» Right ANSWER is (a) 11.55 m/s The EXPLANATION: The MAXIMUM vertical distance is the maximum height. The formula for maximum height is h = (v sinθ) ^2/2g. Here, h = 5, θ = 30°, g = 10. Hence, on solving we will get the initial velocity as 11.55 m/s. The result can be cross checked by putting this value of velocity and finding out the maximum height.

Discussion

41.	A body is moving with a constant velocity of 4î + 3&jcirc;, starting from the origin. What will be the position of the body after 10s?(a) 40î + 30&jcirc;(b) 30î + 40&jcirc;(c) 30î – 40&jcirc;(d) 40î – 30&jcirc;The question was posed to me in semester exam.The doubt is from Motion in a Plane topic in division Motion in a Plane of Physics – Class 11
Answer» The correct CHOICE is (a) 40î + 30&jcirc; The explanation: The BODY’s displacement is given by s = vt. The body starts from the origin hence, the total displacement is the FINAL position of the body. Therefore, after putting in the values, we GET, s = (4î + 3&jcirc;)*10 = 40î + 30&jcirc;.

Discussion

42.	A football is projected at an angle of 45° from the ground with an initial velocity of 10 m/s, take acceleration due to gravity is g = 10 m/s^2.What is the time of flight?(a) 1.4142 s(b) 1.5361 s(c) 1.8987 s(d) 1.5651 sThe question was posed to me in a job interview.The question is from Simple Projectile Motion topic in portion Motion in a Plane of Physics – Class 11
Answer» Right option is (a) 1.4142 s Explanation: The formula for TIME of FLIGHT is t = 2(V sinθ/g). Here, v = 10,θ = 45°, g = 10. HENCE, on solving we will GET the time of flight as 1.4142 s.

Discussion

43.	The vector40î + 30&jcirc; is added to a vector. The result gives 15î + 3&jcirc; as the answer. The unknown vector is _____(a) -25î – 27&jcirc;(b) 25î + 27&jcirc;(c) -25î + 27&jcirc;(d) 25î – 27&jcirc;The question was asked by my college director while I was bunking the class.My enquiry is from Vector Addition topic in chapter Motion in a Plane of Physics – Class 11
Answer» Correct CHOICE is (a) -25î – 27&jcirc; The best I can explain: The REQUIRED vector can be OBTAINED by subtracting 40î + 30&jcirc; from 15î + 3&jcirc;. The RESULT gives -25î – 27&jcirc;. One should pay attention on which vector has to be subtracted from which one.

Discussion

44.	A body is moving with a constant acceleration of 11î + 7&jcirc;, starting from the origin. What will be the position of the body after 10s?(a) 550î + 350&jcirc;(b) 350î + 550&jcirc;(c) 350î – 550&jcirc;(d) 550î – 350&jcirc;The question was asked at a job interview.My question is from Motion in a Plane with Constant Acceleration in portion Motion in a Plane of Physics – Class 11
Answer» Correct answer is (a) 550î + 350&jcirc; To explain: The BODY’s DISPLACEMENT is GIVEN by s = (1/2)at^2. The body starts from the ORIGIN hence, the total displacement is the final position of the body. Therefore, after putting in the values, we get, s = (1/2)(11î + 7&jcirc;)*10^2 = 550î + 350&jcirc;.

Discussion

45.	A car moves 25 units in the positive X direction and 75 units in negative Y direction starting from the origin in 25 seconds. What is the velocity vector of the car?(a) î – 3&jcirc;(b) 3î – &jcirc;(c) î + 3&jcirc;(d) 3î + &jcirc;The question was asked in unit test.My query is from Motion in a Plane with Constant Acceleration topic in chapter Motion in a Plane of Physics – Class 11
Answer» The correct CHOICE is (a) î – 3&JCIRC; The EXPLANATION: The initial position of the car is at the origin and the final position is 25î – 75&jcirc;. Hence the DISPLACEMENT is 25î – 75&jcirc;. The total time taken is 25 s. Hence, the velocity = change in position/time = î – 3&jcirc;.

Discussion

46.	Calculating the relative velocity is an example of ______(a) Vector addition(b) Vector subtraction(c) Vector multiplication(d) Vector divisionThis question was posed to me in an online interview.The query is from Vector Addition in portion Motion in a Plane of Physics – Class 11
Answer» The correct answer is (b) Vector SUBTRACTION To explain I WOULD say: The FORMULA for RELATIVE velocity is, Vector VR = Vector VA – Vector VB. Finding relative velocity is an example of vector subtraction. In fact, finding the relative value for any vector quantity, we need to do vector subtraction.

Discussion

47.	How many variables are required to define the motion of a body in a plane?(a) 1(b) 2(c) 3(d) 4The question was posed to me in an online interview.I'm obligated to ask this question of Motion in a Plane in division Motion in a Plane of Physics – Class 11
Answer» The correct option is (B) 2 Easy EXPLANATION: The motion of a body in a PLANE can be defined by using two variables. These are the two DEFINING axes of the Coordinate system, x and y. Once we have the displacement as a function of these to variables, any other QUANTITY can be found out.

Discussion

48.	A body of weight 20 N, mass 2 kg is moving in vertical circular motion with the help of a string of radius 1 m and with a velocity of 5 m/s. What is the tension in the string at the highest point?(a) 30 N(b) 50 N(c) 20 N(d) 25 NThe question was posed to me in examination.The doubt is from Uniform Circular Motion topic in division Motion in a Plane of Physics – Class 11
Answer» Correct choice is (a) 30 N To ELABORATE: At the highest point, the tension and the weight are in the same direction but the centrifugal force is in the opposite direction. Centrifugal force can be CALCULATED as mv^2/r = 50 N. HENCE the tension = centrifugal force-weight = 30 N.

Discussion

49.	A body of weight 20 N, mass 2 kg is moving in vertical circular motion with the help of a string of radius 1 m and with a velocity of 5 m/s. What is the tension in the string when is horizontal?(a) 30 N(b) 50 N(c) 20 N(d) 25 NI got this question in an interview for internship.The above asked question is from Uniform Circular Motion topic in chapter Motion in a Plane of Physics – Class 11
Answer» Correct choice is (B) 50 N For EXPLANATION: When the string is horizontal, the TENSION in the string and the centrifugal FORCE are opposite to each other. Centrifugal force can be calculated as mv^2/r = 50 N. HENCE the tension = centrifugal force = 50 N.

Discussion

50.	On calculating which of the following quantities, the mass of the body has an effect in simple projectile motion?(a) Velocity(b) Force(c) Time of flight(d) RangeThe question was asked in an online quiz.This key question is from Simple Projectile Motion topic in chapter Motion in a Plane of Physics – Class 11
Answer» Right CHOICE is (b) FORCE The explanation: All mentioned quantities EXCEPT force are kinematic quantities. Force is a kinetic quantity. Force = m x a. Hence, the MASS of the body has an effect on force calculation.

Discussion

Explore topic-wise InterviewSolutions in .

The angular velocity of a stone being rotated is 11 rad/s. What is the angular displacement covered in 0.5s?(a) 5.5 rad(b) 0.55 rad(c) 55 rad(d) 0.5 radThe question was posed to me in my homework.Question is taken from Uniform Circular Motion in chapter Motion in a Plane of Physics – Class 11

The centrifugal force always acts _____(a) Towards the center(b) Away from the center(c) In tangential direction(d) Outside of the plane of motionI got this question in an interview.My query is from Uniform Circular Motion topic in portion Motion in a Plane of Physics – Class 11

The mathematical expression for centripetal force is ______(a) mv^2/r(b) mv/r(c) v^2/r(d) mv^3/rThe question was posed to me in an internship interview.Origin of the question is Uniform Circular Motion topic in portion Motion in a Plane of Physics – Class 11

Which one of the following devices acts on the principle of circular motion?(a) Centrifuge(b) Screw Gauge(c) Ruler(d) Vernier calipersI have been asked this question during an interview for a job.My question is from Uniform Circular Motion topic in chapter Motion in a Plane of Physics – Class 11

When do we get maximum height in a simple projectile motion?(a) When θ = 45°(b) When θ = 60°(c) When θ = 90°(d) When θ = 0°This question was addressed to me in an international level competition.Question is from Simple Projectile Motion in division Motion in a Plane of Physics – Class 11

Unit vector which is perpendicular to the vector 4î + 3&jcirc; is _____(a) &jcirc;(b) î(c) 4î + 3&jcirc;(d) \(\hat{z}\)This question was addressed to me in an online quiz.This interesting question is from Vector Addition topic in chapter Motion in a Plane of Physics – Class 11

In how many independent directions can a vector in a plane be resolved?(a) 1(b) 2(c) 3(d) 4I have been asked this question at a job interview.Question is from Motion in a Plane topic in chapter Motion in a Plane of Physics – Class 11

When do we get maximum range in a simple projectile motion?(a) When θ = 45°(b) When θ = 60°(c) When θ = 90°(d) When θ = 0°The question was posed to me during an internship interview.The doubt is from Simple Projectile Motion in chapter Motion in a Plane of Physics – Class 11

At what angle of projectile (θ) is the horizontal range minimum?(a) θ = 45°(b) θ = 60°(c) θ = 90°(d) θ = 75°The question was asked in quiz.The question is from Simple Projectile Motion topic in division Motion in a Plane of Physics – Class 11

Calculating the relative velocity is an example of ______(a) Vector addition(b) Vector subtraction(c) Vector multiplication(d) Vector divisionThis question was posed to me in an online interview.The query is from Vector Addition in portion Motion in a Plane of Physics – Class 11

How many variables are required to define the motion of a body in a plane?(a) 1(b) 2(c) 3(d) 4The question was posed to me in an online interview.I'm obligated to ask this question of Motion in a Plane in division Motion in a Plane of Physics – Class 11