77 + Interview Questions in MOTION-IN-STRAIGHT-LINE IN GENERAL AWARENESS Page 2 InterviewSolution

51.	A particle starts with an initial velocity 2.0 m/s along the positive x-direction and it accelerations uniformly at the rate of `0.40m//s^(2)` (a) Find the distance travelled by it in the first three seconds. (b) How much time does it take to reach the velocity 9.0 m/s? (c) How much distance will it cover in reaching the velocity 9.0 m/s?
Answer» Given that `y=2m//s, a=0.40m//s^(2)` (a) We have to calculate s when t = 3 s `s=ut+(1)/(2)at^(2)=3xx2+(1)/(2)xx0.40xx3^(2)` `=6+0.20xx9=6+1.80=7.80m` (b) We have to calculate t, when v = 9 m/s As `v=u+at,` So, `t=(v-u)/(a)=(9-2)/(0.4)=(70)/(4)=(35)/(2)=17.5s` (c) Here, s = ?, v = 9 `m//s^(2)`, As `v^(2)=u^(2)+2as` So, `s=(v^(2)-u^(2))/(2a)=(9^(2)-(2)&(2))/(2xx0.4)=(81-4)/(0.8)=(77)/(0.8)=(770)/(8)=(385)/(4)m`

Discussion

52.	A constant force acts on a particle and its displacement x (in cm) is related to the time t (in s) by the equation `t=sqrtx +3`, when the velocity of the particle is zero, its displacement ( in cm) isA. ZeroB. 1C. 2D. 3
Answer» Correct Answer - A

Discussion

53.	A particle located at x = 0 at time t = 0, starts moving along the positive x-direction with a velocity that varies as `v=psqrtx`. The displacement of the particle varies with time as (where, p is constant)A. `t^(3)`B. `t^(2)`C. `t`D. `t^(1//2)`
Answer» Correct Answer - B

Discussion

54.	The velocity versus time graph of two particles moving along x-axis varies are shown in the following two plots. Then A. Maximum separation between two particles is 2 mB. Maximum separation between two particles is 3 mC. Maximum separation between occurs after at t = 2 sD. Maximum separation between occurs after at t = 3 s.
Answer» Correct Answer - B::D

Discussion

55.	Graphs are very useful to represent a physical situation. Various quantities can be easily represented on graphs and other quantites can be determined from the graph. For example the slope of velocity-time graph represents instantaneous acceleration. For a motion with constant acceleration slope of velocity-time graph is constant. If acceleration is changing with time, slope with change and thus velocity-time graph will be a non-linear curve. Further the area of velocity-time graph gives displacement. The velocity-time graph for two objects P and Q are shown. The ratio of their respective acceleration is A. 1B. `sqrt3`C. `(1)/(sqrt3)`D. None of these
Answer» Correct Answer - B

Discussion

56.	Graphs are very useful to represent a physical situation. Various quantities can be easily represented on graphs and other quantites can be determined from the graph. For example the slope of velocity-time graph represents instantaneous acceleration. For a motion with constant acceleration slope of velocity-time graph is constant. If acceleration is changing with time, slope with change and thus velocity-time graph will be a non-linear curve. Further the area of velocity-time graph gives displacement. For the given velocity-time graph the fisplacement of the object vetween t = 2 s to t = 4 s is A. 6 mB. 10 mC. 18 mD. 2 m
Answer» Correct Answer - A

Discussion

57.	Graphs are very useful to represent a physical situation. Various quantities can be easily represented on graphs and other quantites can be determined from the graph. For example the slope of velocity-time graph represents instantaneous acceleration. For a motion with constant acceleration slope of velocity-time graph is constant. If acceleration is changing with time, slope with change and thus velocity-time graph will be a non-linear curve. Further the area of velocity-time graph gives displacement. A car starts from rest with a constant acceleration `a_(1)` for some time and attains a velocity `v_(0)`. Then it immediately retards at a constant rate `a_(2)` to rest. The total time to journey is `t_(0)` Identify the correct velocity-time graphA. B. C. D. None of these
Answer» Correct Answer - A

Discussion

58.	Graphs are very useful to represent a physical situation. Various quantities can be easily represented on graphs and other quantites can be determined from the graph. For example the slope of velocity-time graph represents instantaneous acceleration. For a motion with constant acceleration slope of velocity-time graph is constant. If acceleration is changing with time, slope with change and thus velocity-time graph will be a non-linear curve. Further the area of velocity-time graph gives displacement. For the given velocity-time graph the possibly correct acceleration-time relationship is A. Acceleration is constantB. Acceleration is increasing with timeC. Acceleration is decreasing with timeD. None of these
Answer» Correct Answer - B

Discussion

59.	Graphs are very useful to represent a physical situation. Various quantities can be easily represented on graphs and other quantites can be determined from the graph. For example the slope of velocity-time graph represents instantaneous acceleration. For a motion with constant acceleration slope of velocity-time graph is constant. If acceleration is changing with time, slope with change and thus velocity-time graph will be a non-linear curve. Further the area of velocity-time graph gives displacement. For the above situation let `t_(1)` be the time of accelerated motion and `t_(2)` be the time or retarded motion, then the correct relation isA. `a_(1)t_(2)=a_(2)t_(1)`B. `a_(1)t_(1)=a_(2)t_(2)`C. `a_(1)t_(1)^(2)=a_(2)t_(2)^(2)`D. `a_(1)t_(2)^(2)=a_(2)t_(1)^(2)`
Answer» Correct Answer - B

Discussion

60.	A fishing boat is anchored 9 km away from the the nearest point on the shore. A messanger must be sent from the fishing boat to a camp, 15 km from the point on shore closest to boat. If the messanger can walk at a speed of 5 km per hour and can row at 4 km/h. determine the distance of that point (in km) from the shore, where he must land so as to reach the shore in least possible time.
Answer» Correct Answer - 4

Discussion

61.	STATEMENT - 1 : A positive acceleration of a body can be associated with a slowing down of the body. and STATEMENT - 2 : Acceleration is a vector quantity.A. Statement-1 is True, Statement-2 is True, Statement-2 is a correct explanation for Statement-5B. Statement-1 is True, Statement-2 is True, Statement-2 is NOT a correct explanation for Statement-5C. Statement-1 is True, Statement-2 is FalseD. Statement-1 is False, Statement-2 is True
Answer» Correct Answer - B

Discussion

62.	Figure shows the velocity of a particle moving on x-axis. Which of the following statement is correct for the interval shown in graph?A. Speed of particle is increasing continuouslyB. The particle changes its direction of motion at some point of timeC. The particle does not return to its starting point at the end of the intervalD. The acceleration of particle changes from `-ve` to `+ve`
Answer» Correct Answer - B::C

Discussion

63.	A body starts from rest with an acceleration `2m//s^(2)` till it attains the maximum velocity then retards to rest with `3m//s^(2)`. If total time taken is 10 second, then maximum speed attained isA. 12 m/sB. 8 m/sC. 6 m/sD. 4 m/s
Answer» Correct Answer - A

Discussion

64.	Two trains each of length 100 m are moving with speeds 54 km/h (for Train - 1) and 90 km/h (for Train-2) on two parallel tracks. Match the entries given in column I with the entries given in column II `{:(" Column I"," Column II"),("(A) Time taken in passing (in s)","(p) 125"),("(B) Distance travelled by "1^(st)" train during passing (in m)","(q) 500"),("(C) Distance travelled by "2^(nd)" train during passing (in m)","(r) 20"),(" if both trains are moving in same direction",),("(D) Displacement of "1^(st)" train w.r.t. 2"^(nd)" train in 2 s (in m)","(s) 300"),(,"(t) 5"):}`
Answer» Correct Answer - A(r, t), B(s), C(q), D(r)

Discussion

65.	A train of length 120 m travels at a speed of 57 km/h. In what time it will pass a man who is walking at 3 km/h in the opposite direction?
Answer» Correct Answer - 7.2 s. Hint : `v_(AB)=v_(A)+v_(B)`, relative velocity A w.r.t. B

Discussion

66.	Two train are moving in a straight line in the same direction with a speed of 80 km/h. The relative velocity of one trains w.r.t. each other isA. 80 km/hB. 40 km/hC. ZeroD. 160 km/h
Answer» Correct Answer - C

Discussion

67.	Two cars are moving is one a same line dimension in opposite direction with the same speed v. The relative velocity of two cars w.r.t. each other isA. 2 vB. vC. `(v)/(2)`D. Zero
Answer» Correct Answer - A

Discussion

68.	Two objects A and B are walking with speed 6 km/h and 10 km/h respectively in the same direction. Find the relative displacement of B w.r.t. A after 4 hours.
Answer» Correct Answer - 16 km. Hint : Relative velocity is the rate of change of relative position w.r.t. time

Discussion

69.	The relative velocity of two objects A and B is 10 m/s. If the velocity of object A is 40 m/s then the velocity with which B is moving is (assume both objects are moving in same direction)A. 10 m/sB. 40 m/sC. 30 m/sD. 15 m/s
Answer» Correct Answer - C

Discussion

70.	Two objects A and B are moving in opposite directions with velocities `v_(A) and v_(B)` respectively, the magnitude of relative velocity of A w.r.t. B isA. `v_(A)-v_(B)`B. `v_(A)+v_(B)`C. `v_(B)-v_(A)`D. `v_(A)//v_(B)`
Answer» Correct Answer - A

Discussion

71.	Which graph represents an objects at rest ?A. B. C. D.
Answer» Correct Answer - A

Discussion

72.	Two objects A and B are moving with velocities `v_(A) and v_(B)` respectively along positive x-axis. If `v_(A) lt v_(B)` then, which of the following position-time graphs is correctly showing the velocity of A and B ?A. B. C. D.
Answer» Correct Answer - B

Discussion

73.	If the relation between acceleration and time for an object is given by `a=2t+4t^(2)` Calculate the position of object from the origin at t = 4 s. Assume the object to be at rest at `t=0`.
Answer» Correct Answer - 106.6 m. Hint : First integrate the given expression to get velocity and again integrate it to get the position.

Discussion

74.	A ball is thrown vertically upward. What is the magnitude of velocity at the highest point ?
Answer» Correct Answer - Zero. Hint : After reaching the highest point the ball will come back to the thrower.

Discussion

75.	A ball is thrown vertically upward attains a maximum height of 45 m. The time after which velocity of the ball become equal to half the velocity of projection ? (use g = 10 `m//s^(2)`)A. 2 sB. 1.5 sC. 1 sD. 0.5 s
Answer» Correct Answer - B

Discussion

76.	A ball is thrown vertically upward from the top of a tower with a speed of 100 m/s. It strikes the pond near the base of the tower after 25 second. The height of the tower isA. 500 mB. 125 mC. 625 mD. 425 m
Answer» Correct Answer - C

Discussion

77.	The position of a particle along the x-axis is given by the equation, `x=t^(3)-6t^(2)+9t`, where t is measured in seconds and x in meters. (a) Find the velocity at time t (b) What is the velocity at t = 2 s, at = t = 4 s? (c) What is the time instant, when particle is at rest?
Answer» Strategy : Velocity `=(dx)/(dt)` i.e., change in position of particle with respect to time. Given that , `x=t^(3)-6t^(2)+9t` (a) `v=(dx)/(dt)=3t^(2)-12t+9` (b) `v_(t)=2=3(2)^(2)-12(20+9=3xx4-24+9=12-24+9=21-24=-3m//s` `v_(t)=4=3(4)^(2)-12(4)+9=3xx16-48+9=48+9=9m//s` (c) `v_((t))=0 rArr 3t^(2)-12t+9=0 rArr 3(t^(2)-4t+3)=0 rArr 3(t-1)(t-3)=0` This is true when t = 1 or t = 3 thus, the particle is at rest at t = 1 s and at t = 3 s.

Discussion

Explore topic-wise InterviewSolutions in .

A constant force acts on a particle and its displacement x (in cm) is related to the time t (in s) by the equation `t=sqrtx +3`, when the velocity of the particle is zero, its displacement ( in cm) isA. ZeroB. 1C. 2D. 3

A particle located at x = 0 at time t = 0, starts moving along the positive x-direction with a velocity that varies as `v=psqrtx`. The displacement of the particle varies with time as (where, p is constant)A. `t^(3)`B. `t^(2)`C. `t`D. `t^(1//2)`

A body starts from rest with an acceleration `2m//s^(2)` till it attains the maximum velocity then retards to rest with `3m//s^(2)`. If total time taken is 10 second, then maximum speed attained isA. 12 m/sB. 8 m/sC. 6 m/sD. 4 m/s

A train of length 120 m travels at a speed of 57 km/h. In what time it will pass a man who is walking at 3 km/h in the opposite direction?

Two train are moving in a straight line in the same direction with a speed of 80 km/h. The relative velocity of one trains w.r.t. each other isA. 80 km/hB. 40 km/hC. ZeroD. 160 km/h

Two cars are moving is one a same line dimension in opposite direction with the same speed v. The relative velocity of two cars w.r.t. each other isA. 2 vB. vC. `(v)/(2)`D. Zero

Two objects A and B are walking with speed 6 km/h and 10 km/h respectively in the same direction. Find the relative displacement of B w.r.t. A after 4 hours.

The relative velocity of two objects A and B is 10 m/s. If the velocity of object A is 40 m/s then the velocity with which B is moving is (assume both objects are moving in same direction)A. 10 m/sB. 40 m/sC. 30 m/sD. 15 m/s

Two objects A and B are moving in opposite directions with velocities `v_(A) and v_(B)` respectively, the magnitude of relative velocity of A w.r.t. B isA. `v_(A)-v_(B)`B. `v_(A)+v_(B)`C. `v_(B)-v_(A)`D. `v_(A)//v_(B)`

Which graph represents an objects at rest ?A. B. C. D.

Two objects A and B are moving with velocities `v_(A) and v_(B)` respectively along positive x-axis. If `v_(A) lt v_(B)` then, which of the following position-time graphs is correctly showing the velocity of A and B ?A. B. C. D.

If the relation between acceleration and time for an object is given by `a=2t+4t^(2)` Calculate the position of object from the origin at t = 4 s. Assume the object to be at rest at `t=0`.

A ball is thrown vertically upward. What is the magnitude of velocity at the highest point ?

A ball is thrown vertically upward attains a maximum height of 45 m. The time after which velocity of the ball become equal to half the velocity of projection ? (use g = 10 `m//s^(2)`)A. 2 sB. 1.5 sC. 1 sD. 0.5 s

A ball is thrown vertically upward from the top of a tower with a speed of 100 m/s. It strikes the pond near the base of the tower after 25 second. The height of the tower isA. 500 mB. 125 mC. 625 mD. 425 m

The position of a particle along the x-axis is given by the equation, `x=t^(3)-6t^(2)+9t`, where t is measured in seconds and x in meters. (a) Find the velocity at time t (b) What is the velocity at t = 2 s, at = t = 4 s? (c) What is the time instant, when particle is at rest?