31 + Interview Questions in DESCRIPTION-OF-MOTION IN GENERAL AWARENESS Page 1 InterviewSolution

1.	Two partides. are thrown from the same point in the same vertical plane, as shown in figure simultaneously. Then indicate the correct statements : A. Time of flight for B is less than that of AB. Projection speed of B is greater than that of AC. Horizontal component of velocities of B is greater than that of AD. The vertical component of velocities of both A and B are always equal throughout the duration for which both the particles in air
Answer» Correct Answer - B::C::D

Discussion

2.	A stone is released from an elevator going up with an acceleration a. The acceleration of the stone after the release isA. a upwardB. (g - a) upwardC. (g - a) downwardD. g downward
Answer» Correct Answer - D

Discussion

3.	A hollow vertical cylinder of radius R and height h has smooth internal suface. A small particle is placed in contact with the inner side of the upper rim at a point P. It is given a horizontal speed `v_(0)` tangential to rim. It leaves the lower rim point Q vertically below P. The number of revolutions made by the particle will:A. `h/(2piR)`B. `(v_(0))/(sqrt(2gh))`C. `(2piR)/(h)`D. `(v_(0))/(2piR)(sqrt((2h)/(g)))`
Answer» Correct Answer - D

Discussion

4.	A block is kept on the floor of an elevator. The elevator starts descending with an acceleration of 12`m//s^(2)` the displacement of the block during `1^(st)` one second wth respect to elevator is-A. 1m downwardsB. 1 m upwardsC. 5m downwardsD. zero meter.
Answer» Correct Answer - B

Discussion

5.	A rod of length I leans by its upper end against a smooth vertical wall, while its other end leans against the floor. The end that leans against the wall moves uniformly downward. Then: A. The other end also moves uniformlyB. The speed of other end goes on decreasingC. The speed of other end goes on increasingD. The speed of other end first decreases and thenincreases
Answer» Correct Answer - B

Discussion

6.	A body travelling along a straight line , one thired of the total distance with a velocity ` 4 ms^(-1)`. The remaining part of the distance was covered with a velocity ` 2 ms^(-1)` for half the time and with velocity ` 6 ms^(-1)` for the other half of time . What is the mean velocity averaged over te whle time of motin ?A. 5m/sB. 4m/sC. `4.5m//s`D. `3.5m//s`
Answer» Correct Answer - B

Discussion

7.	An aeroplane moving horizontally from west to east with some velocity and with an acceleration `5m//s^(2)` drops a food packet at some instant. Then:A. The path of the packet is parabolic with respect to groundB. A person sitting on the aeroplane shall see the packet is always vertically below the plane.C. With respect to plane the packet travels in a straight line making an angle `"tan"^(1) (1//2)` east of vertical.D. With respect to plane the packet travels in a straight line making an angle `"tan" ^(-1) (1//2)` east of vertical.
Answer» Correct Answer - A::C

Discussion

8.	A particle has an initial velocity of `9m//s` due east and a constant acceleration of `2m//s^(2)` due west. The displacement coverd by the particle in the fifth second of its motion is :A. zeroB. 0.5mC. 2mD. None
Answer» Correct Answer - B

Discussion

9.	A plane is inclined at an angle `30^(@)` with horizontal. The component of a vector `vec(A)= -10k` perpendicular to this plane is: (here z-direction is vertically upwards)A. `5 sqrt(2)`B. `5 sqrt(3)`C. `5`D. `2.5`
Answer» Correct Answer - B

Discussion

10.	Two particles, 1 and 2, move with constant velocities `v_1` and `v_2`. At the initial moment their radius vectors are equal to `r_1` and `r_2`. How must these four vectors be interrelated for the particles to collide?A. `(vecr_(1)-vecr_(2))/(\|vecr_(1)-vecr_(2)\|)=(vecv_(1)-vecv_(2))/(\|vecr_(1)-vecv_(2)\|`B. `(vecr_(1)-vecr_(2))/(\|vecr_(1)-vecr_(2)\|)=(vecv_(2)-vecv_(1))/(\|vecr_(2)-vecv_(1)\|`C. `(vecr_(1)-vecr_(2))/(\|vecr_(2)-vecr_(1)\|)=(vecv_(2)-vecv_(1))/(\|vecr_(1)-vecv_(2)\|`D. None of these
Answer» Correct Answer - B

Discussion

11.	For a constant initial speed and for constant angle of projection of a projectile the change dR in its horizontal range R due to a change dg in value of gravitational acceleration g is governed by the relation:A. `(dR)/(R)=(dg)/(g)`B. `(dR)/(R)=(-dg)/(g)`C. `(dR)/(g)=(dg)/(R)`D. `(dR)/(g)=(-dg)/(R)`
Answer» Correct Answer - B

Discussion

12.	Two projectiles `A` and `B` are projected with an angle of projection `15^(@)` for the projectile `A` and `45^(@)` for the projectile `B`. If `R_(A)` and `R_(B)` be the horizontal range for the two projectiles, thenA. `R_(A) lt R_(B)`B. `R_(A) = R_(B)`C. `R_(A) gt R_(B)`D. The information is insufficient to decide the relation of `R_(A)` with `R_(B)`.
Answer» Correct Answer - D

Discussion

13.	Three particles start from origin at the same time: one with velocity `v^(1)` along positive x-axis, the second along the positive y-axis with a velocity `v^(2)` and the third along the line y = x with such a speed that all the three always stay in a straight line, then velocity of the third particles is:A. `sqrt(v_(1)v_(2))`B. `(v_(1)+v_(2))/(2)`C. `(v_(1)v_(2))/(sqrt(v_(1)^(2)+v_(2)^(2)))`D. `(v_(1)v_(2)sqrt2)/(v_(1)+v_(2))`
Answer» Correct Answer - D

Discussion

14.	An open lift is coming down from the top of building at a constant speed `v=10m//s`. A boy standing on the lift throws a stone vertically upwards at a speed of 30 m/s w.r.t. himself. The time after which he will catch the stone is:A. 4 secB. 6 secC. 8 secD. 10 sec
Answer» Correct Answer - B

Discussion

15.	A person standing near the edge of the top of a building throws two balls A and B. The ball A is thrown vertically upward and B is thrown vertically downward with the same speed. The ball A hits the ground with speed `v_A` and the ball B hits the ground wiht a speed `v_B`. We haveA. `v_(A) gt v_(B)`B. `v_(A) lt v_(B)`C. `v_(A) =v_(B)`D. The relation between `v _(A)` and `v_( B)` depends on height of the building above the ground.
Answer» Correct Answer - C

Discussion

16.	The X and Y - component of ` vec (p) ` are `7hat(i) and 6hat(j)`. Also , the X and Y-components of `vec(p)+vec(Q)` are `11 hat(i) and 9 hat (j)` respectively. Then magnitude of `vec(Q)` is :A. 7B. 6C. 5D. 13
Answer» Correct Answer - C

Discussion

17.	Two vector `vec(A)=2 hat(i) +3hat(j)-4hat(k)` and `vec(B)=4hat(i) + 8hat(j) +x hat(k)` are such that the component of `vec(B) ` along `vec(A)` is zero . Then the value of x will be :A. 8B. -4C. 4D. -8
Answer» Correct Answer - A

Discussion

18.	Two vector `vec(A)=3hat(i) +8 hat(j) -2hat(k)` and `vec(B)=6hat(i)+16 hat(j) +x hat(k)` are such that the component of `vec(B)` perpendicular to `vec(A)` is zero . Then the value of x will be :A. 8B. -4C. 4D. -8
Answer» Correct Answer - B

Discussion

19.	At what angle the vector `(vec(A)+vec(B))` and `(vec(A)-vec(B))` must act, so that the resultant is `sqrt(A^(2)_B^(2))`A. `cos^(-1)((A^(2)-B^(2))/(A^(2)+B^(2)))`B. `cos^(-1)((A^(2)+B^(2))/(A^(2)-B^(2)))`C. `cos^(-1)((A^(2)-B^(2))/(2(A^(2)+B^(2))))`D. `cos^(-1)((A^(2)+B^(2))/(2(B^(2)-A^(2))))`
Answer» Correct Answer - D

Discussion

20.	Velocity versus displacement graph of a particle moving in a straight line is shown in figure. Corresponding acceleration versus velocity graph will be. A. B. C. D.
Answer» Correct Answer - A

Discussion

21.	The velocity-time graph of a particle moving along a straight line is given as below. The displacement time curve for the particle is given by : A. B. C. D.
Answer» Correct Answer - C

Discussion

22.	A particle moving with uniform acceleration from `A` to `B` along a straight line has velocities `v_(1)` and `v_(2)` at `A` and `B` respectively. If `C` is the mid-point between `A` and `B` then determine the velocity of the particle at `C` . .A. `aV_(1)=bV_(2)`B. `aV_(1)V^(2)=bV_(2)^(2)`C. `a^(2)V_(1)=b^(2)V_(2)`D. `aV_(2)=bV_(1)`
Answer» Correct Answer - D

Discussion

23.	Two straight lines `l_(1)` and `l_(2)` cross each other ar point P The line `l_(1)` is moving at a speed `v_(1)` perpendicular to itself & line `l_(2)` is moving at a speed `v_(2)` in the similar fashion. The speed of point P is : A. `sqrt((v_(1)v_(2))/(sinalpha))`B. `sqrt(v_(1)^(2)+v_(2)^(2)+2(v_(1)+v_(2))^(2)cosalpha)/(cosalpha)`C. `sqrt(v_(1)^(2)+v_(2)^(2)+2(v_(1)+v_(2))^(2)cosalpha)/(sinalpha)`D. `((v_(1)+v_(2))+sqrt(v_(1)v_(2))cosalpha)/(cosalpha)`
Answer» Correct Answer - C

Discussion

24.	The quantity `int_(t_(1))^(t_(2)) vec(V)`dt represents:A. Distance travelled during `t_(1) to t_(2)`B. Displacement during `t_(1) to t_(2)`C. Average acceleration during `t_(1) to t_(2)`D. None of these
Answer» Correct Answer - B

Discussion

25.	If `vec(A)=vec(B)+vec(C)` and the magnitude of `vec(A), vec(B) and vec(C)` are 5, 4, and 3 units respectively the angle between `vec(A) and vec(B)` is :A. `cos^(-1)((3)/(5))`B. `cos^(-1)((4)/(5))`C. `((pi)/(2))`D. `sin^(-1)((4)/(5))`
Answer» Correct Answer - B

Discussion

26.	If `vec(a_(1)) and vec(a_(2))`are two non-collinear unit vectors and if `\|vec(a_(1)) + vec(a_(2))\|=sqrt(3)`, then the value of `(vec(a_(1))-vec(a_(2))). (2 vec(a_(1))+vec(a_(2)))` is :A. `2`B. `3//2`C. `1//2`D. `1`
Answer» Correct Answer - C

Discussion

27.	Two vectors `vec(A)` and `vec(B)` have magnitudes 2 and `2sqrt(2)` respectively. It is found that `vec(A).vec(B) = \|vec(A) xx vec(B)\|`, then the value of `\|(vec(A)+vec(B))/(vec(A)-vec(B))\|` will be :A. 5B. `sqrt(5)`C. `(sqrt(2)+1)/(sqrt(2)-1)`D. `(sqrt(2)-1)/(sqrt(2)+1)`
Answer» Correct Answer - B

Discussion

28.	If the resultant of two vectors having magnitudes of 7 and 4 is 3, then the magnitude of the cross product of the two vectors will be:A. 28B. `sqrt(65)`C. `sqrt(33)`D. zero
Answer» Correct Answer - D

Discussion

29.	A particle is projected from the ground at an angle of `60^(@)` with horizontal at speed `u = 20 m//s.` The radius of curvature of the path of the particle, when its velocity. makes an angle of `30^(@)` with horizontal is : `(g=10 m//s^(2)`A. `10.6 m`B. `12.8 m`C. `15.4 m`D. `24.2 m`
Answer» Correct Answer - C

Discussion

30.	When a body is thrown up in a lift with a velocity `u` relative to the lift, the time of flight is found to be `t`. The acceleration with which the lift is moving up isA. `((u-g t))/(t)` upwardsB. `((u-g t))/(t)` downwardsC. `((2u-g t))/(t)` upwardsD. `((2u-g t))/(t)` downwards
Answer» Correct Answer - C

Discussion

31.	The sum of two forces at a point is 16N. if their resultant is normal to the smaller force and has a magnitude of 8N, then two forces areA. 6N and 10 NB. 8N and 8 NC. 4N and 12ND. 2 N and 14 N
Answer» Correct Answer - A

Discussion

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A stone is released from an elevator going up with an acceleration a. The acceleration of the stone after the release isA. a upwardB. (g - a) upwardC. (g - a) downwardD. g downward

A block is kept on the floor of an elevator. The elevator starts descending with an acceleration of 12`m//s^(2)` the displacement of the block during `1^(st)` one second wth respect to elevator is-A. 1m downwardsB. 1 m upwardsC. 5m downwardsD. zero meter.

A particle has an initial velocity of `9m//s` due east and a constant acceleration of `2m//s^(2)` due west. The displacement coverd by the particle in the fifth second of its motion is :A. zeroB. 0.5mC. 2mD. None

A plane is inclined at an angle `30^(@)` with horizontal. The component of a vector `vec(A)= -10k` perpendicular to this plane is: (here z-direction is vertically upwards)A. `5 sqrt(2)`B. `5 sqrt(3)`C. `5`D. `2.5`

For a constant initial speed and for constant angle of projection of a projectile the change dR in its horizontal range R due to a change dg in value of gravitational acceleration g is governed by the relation:A. `(dR)/(R)=(dg)/(g)`B. `(dR)/(R)=(-dg)/(g)`C. `(dR)/(g)=(dg)/(R)`D. `(dR)/(g)=(-dg)/(R)`

An open lift is coming down from the top of building at a constant speed `v=10m//s`. A boy standing on the lift throws a stone vertically upwards at a speed of 30 m/s w.r.t. himself. The time after which he will catch the stone is:A. 4 secB. 6 secC. 8 secD. 10 sec

The X and Y - component of ` vec (p) ` are `7hat(i) and 6hat(j)`. Also , the X and Y-components of `vec(p)+vec(Q)` are `11 hat(i) and 9 hat (j)` respectively. Then magnitude of `vec(Q)` is :A. 7B. 6C. 5D. 13

Two vector `vec(A)=2 hat(i) +3hat(j)-4hat(k)` and `vec(B)=4hat(i) + 8hat(j) +x hat(k)` are such that the component of `vec(B) ` along `vec(A)` is zero . Then the value of x will be :A. 8B. -4C. 4D. -8

Two vector `vec(A)=3hat(i) +8 hat(j) -2hat(k)` and `vec(B)=6hat(i)+16 hat(j) +x hat(k)` are such that the component of `vec(B)` perpendicular to `vec(A)` is zero . Then the value of x will be :A. 8B. -4C. 4D. -8

At what angle the vector `(vec(A)+vec(B))` and `(vec(A)-vec(B))` must act, so that the resultant is `sqrt(A^(2)_B^(2))`A. `cos^(-1)((A^(2)-B^(2))/(A^(2)+B^(2)))`B. `cos^(-1)((A^(2)+B^(2))/(A^(2)-B^(2)))`C. `cos^(-1)((A^(2)-B^(2))/(2(A^(2)+B^(2))))`D. `cos^(-1)((A^(2)+B^(2))/(2(B^(2)-A^(2))))`

Velocity versus displacement graph of a particle moving in a straight line is shown in figure. Corresponding acceleration versus velocity graph will be. A. B. C. D.

The velocity-time graph of a particle moving along a straight line is given as below. The displacement time curve for the particle is given by : A. B. C. D.

The quantity `int_(t_(1))^(t_(2)) vec(V)`dt represents:A. Distance travelled during `t_(1) to t_(2)`B. Displacement during `t_(1) to t_(2)`C. Average acceleration during `t_(1) to t_(2)`D. None of these

If `vec(A)=vec(B)+vec(C)` and the magnitude of `vec(A), vec(B) and vec(C)` are 5, 4, and 3 units respectively the angle between `vec(A) and vec(B)` is :A. `cos^(-1)((3)/(5))`B. `cos^(-1)((4)/(5))`C. `((pi)/(2))`D. `sin^(-1)((4)/(5))`

If `vec(a_(1)) and vec(a_(2))`are two non-collinear unit vectors and if `|vec(a_(1)) + vec(a_(2))|=sqrt(3)`, then the value of `(vec(a_(1))-vec(a_(2))). (2 vec(a_(1))+vec(a_(2)))` is :A. `2`B. `3//2`C. `1//2`D. `1`

Two vectors `vec(A)` and `vec(B)` have magnitudes 2 and `2sqrt(2)` respectively. It is found that `vec(A).vec(B) = |vec(A) xx vec(B)|`, then the value of `|(vec(A)+vec(B))/(vec(A)-vec(B))|` will be :A. 5B. `sqrt(5)`C. `(sqrt(2)+1)/(sqrt(2)-1)`D. `(sqrt(2)-1)/(sqrt(2)+1)`

If the resultant of two vectors having magnitudes of 7 and 4 is 3, then the magnitude of the cross product of the two vectors will be:A. 28B. `sqrt(65)`C. `sqrt(33)`D. zero

A particle is projected from the ground at an angle of `60^(@)` with horizontal at speed `u = 20 m//s.` The radius of curvature of the path of the particle, when its velocity. makes an angle of `30^(@)` with horizontal is : `(g=10 m//s^(2)`A. `10.6 m`B. `12.8 m`C. `15.4 m`D. `24.2 m`

When a body is thrown up in a lift with a velocity `u` relative to the lift, the time of flight is found to be `t`. The acceleration with which the lift is moving up isA. `((u-g t))/(t)` upwardsB. `((u-g t))/(t)` downwardsC. `((2u-g t))/(t)` upwardsD. `((2u-g t))/(t)` downwards

The sum of two forces at a point is 16N. if their resultant is normal to the smaller force and has a magnitude of 8N, then two forces areA. 6N and 10 NB. 8N and 8 NC. 4N and 12ND. 2 N and 14 N