InterviewSolution
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InterviewSolution
This section includes InterviewSolutions, each offering curated multiple-choice questions to sharpen your knowledge and support exam preparation. Choose a topic below to get started.
| 51. |
An alpha particle collides elastically with a stationary nucleus and continues on at an angleof `60^(@)` with respect to the original direction of motion. The nucleus recoils at an angle of `30^(@)` with respect to this direction. Mass number of nucleus isA. 2B. 4C. 8D. 6 |
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Answer» Correct Answer - B |
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| 52. |
Two balls of equal mass have a head-on collision with speed `6 m//s`. If the coefficient of restitution is `(1)/(3)`, find the speed of each ball after impact in `m//s`A. `18 m//s`B. `2m//s`C. `6m//s`D. `4m//s` |
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Answer» Correct Answer - B |
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| 53. |
Mass `m_(1)` hits `m_(2)` with inelastic impact (e=0) while slliding horizontally with velocity v along the common line of centres of three equal mass as shoun in fugure `-4.155.` Initially, masses `m_(2)` and `m_(3)` are stationary and the spring is unstressed. Find: |
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Answer» Correct Answer - `"["v/2,0(2)/9mv^(2),(mv^(2))/72,(sqrt(mv^(2)))/(6k)"]"` |
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| 54. |
A ball of mass `m` is released from A inside a smooth wedge of mass `m` as shown in figure. What is the speed of the wedge when the ball reaches point B? A. `((gR)/(3sqrt(2)))^(1//2)`B. `sqrt(2gR)`C. `((5gR)/(2sqrt(3)))^(1//2)`D. `sqrt(3/2gR)` |
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Answer» Correct Answer - A |
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| 55. |
A ball of mass m moving horizontally at a speed v collides with the bob of a simple pendulum at rest. The mass of the bob is also m. If the collision is perfectly inelastic and both balls sticks, the height to which the two balls rise after the collision will be given by:A. `v^(2)/(g)`B. `v^(2)/(2g)`C. `v^(2)/(4g)`D. `v^(2)/(8g)` |
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Answer» Correct Answer - D |
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| 56. |
`N` identical balls are placed on a smooth horizontal surface. An another ball of same mass collides elastically with velocity `u` with first ball of `N` balls. A process of collision is thus started in which first ball collides with second ball and the with the third ball and so on. The coefficient of restitution for each collision is `e`. Find the speed of `Nth` ball. |
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Answer» Correct Answer - `[(u(1+e)^(N-1))/(2^(N-1))]` |
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| 57. |
A ball of mass `m` moving at speed `v` makes a head on collision with an identical ball at rest. The kinetic energy of the balls after the collision is `3//4th` of the original. Find the coefficient of restitution. |
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Answer» Correct Answer - `[(1)/(sqrt2)]` |
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| 58. |
While moving in a wagon `(5 kg)`along a smoth road at `0.5` m/s, a `15` kg boy throws a `3` kg bag of send in front of him with a speed `4` m/s relative to his original motion. How fast is he moving after he throws the bag of send. What is his final direction of motion ? |
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Answer» Correct Answer - `"["0.1m//"backword"]"` |
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| 59. |
A simple pendulum of length l and consisting of a ball of mass m is released from a position making an angle `theta=cos^(-1)` (0.8) with the vertical and strikes at its lowest position a block of mass M resting on a rough horizontal plane. If the coefficient of kinetic friction between the plane and the block is 0.2 find (a) How long the block will move along the plane, if the ball of the pendulum rebounds to an angle `beta=cos^(-1)` (0.9)A (b) The coefficient of restitution, use `(M)/(m) =10` and 1= 1 m |
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Answer» Correct Answer - `[2.916 cm,0876]` |
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| 60. |
Two billiard balls of equal mass move at tight angles and meet at the origin of a coordinate system. First is moving up along the y-axis with speed `4.8` m/s. After the elestic collision, the second ball is moving along the positive y-axis. What is the final direction of the first ball, and what are their two speed. ? |
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Answer» Correct Answer - `"["+x"direction,"4.8m//s,3m//s"]"` |
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| 61. |
A wagon of mass `M` can move without friction along horizontal rails. A simple pendulum consisting of a sphere of mass `m` is suspended from the ceiling of the wagon by a string of length l. At the initial moment the wagon and the pendulum are at rest and the string is deflected through an angle `alpha` from the vertical. Find the velocity of the wagon when the pendulum passes through its mean position. |
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Answer» Correct Answer - `"["2m sin (alpha//2)sqrt((gl)/((M+m)M))"]"` |
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| 62. |
The tennis ball may leave the racket of a top player on the serve with a speed of `65` m/s If mass of the ball is `0.06` kg and is in bontact with the racket for `0.03` sec, what the average force n the ball ? |
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Answer» Correct Answer - `"["130N"]"` |
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| 63. |
Three particles` A, B` and `C` of equal mass move with equal speed `V = 5 ms^(-1)` along the medians of an equilateral triangle as shown in the figure. They collide at the centroid `G` of the triangle. After the collision, `A` comes to rest, `B` retraces its path with the speed `V = 5 ms^(-1)`. What is the speed of `C`? |
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Answer» Correct Answer - `"["V"]"` |
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| 64. |
A `4200` kg rocket is traveling in outer space with a velocity of `150` m/s toward the sun. It wishes to alter its course by `30^(@),` and can do this by shooting its rockets briefly in a direction perpendicular to its original motion. If the rocket gases are expelled at a speed of `2700` m/s, what mass of gas must be explled ? |
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Answer» Correct Answer - `"["131 kg "]"` |
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| 65. |
The sum of all the external forces on a system of particles is zero. Which of the following must be true for the system of particles ?A. the total mechanical energy is constantB. the total potential energy is constantC. the total kinetic-energy is constantD. the total momentum is constant |
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Answer» Correct Answer - A::D |
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| 66. |
Find the mass of the rocket as a function of time, if it moves with a constant acceleration `a`, in absence of external forces. The gas escapes with a constant velocity `u` relative to the rocket and its mass initially was `m_0`. |
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Answer» Correct Answer - `"["m=m_(o)e^(-(alu)t)"]"` |
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| 67. |
A body has its centre of maas at the origin. The x-coordinates of the particlesA. May be all positiveB. May be all negativeC. May be all non-negativeD. May be positive for some case and negative in other cases |
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Answer» Correct Answer - C::D |
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| 68. |
A system of particles is acted upon by a constant nonzero external force. If `v` and `a` are instantaneous velocity and acceleration of the centre of mass, then it is possible that at a given instantA. `v_(0)=0,a_(0)=0`B. `v_(0)=0,a_(0)ne0`C. `v_(0)ne 0, a_(0)=0`D. `v_(0)ne0,a_(0)ne0` |
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Answer» Correct Answer - B::D |
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| 69. |
A long block A is at rest on a smooth horizontal surface. A small block B, whose mass is half of A, is placed on A at one end and projected along A with some velocity u. The coefficient of friction between the blocks is `mu`: A. The blocks will reach the final common velocity `u/3`B. the work done against friction is two-thirds of the initial kinetic energy of BC. before the block reach a common velocity the acceleration of A relative to B is `2/3 mu g.`D. Before the blocks reach a common velocity the acceleration of A relative to B is `3/2 mu g.` |
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Answer» Correct Answer - A::B::D |
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| 70. |
In one-dimensional collision between two identical particles A and B,B is stationary and A has momentum p before and after the impact, and(P-J) during the impact:A. the total momentum of the A plus B, system is P before and after the impact and (P-J) during the impact.B. During the impact A gives impules J to BC. the coefficient of restitution is `(2J)/(P) -1`D. the coefficient of restitution is `J/P +1` |
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Answer» Correct Answer - A::C |
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| 71. |
In an elastic collision between spheres A and B of equal mass but unequal radii, A moves along the x-axis and B is stationary before impact. Which of the following is possible after impact ?A. A comes to restB. The velocity of B relative to A remains the same in magnitude but reverses in directionC. A and B move with equal speeds, making an angle of `45^(@)` each with the x-axisD. A and B move with unequal speeds, making angles of `30^(@)` and `60^(@)` with the x-axis respectively. |
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Answer» Correct Answer - A::B::C::D |
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