Collisions

IMPORTANT

Collisions: Overview

This topic covers concepts, such as, Collisions, Inelastic Collision, Linear Impulse and Coefficient of Restitution & Collision and Vertical Circular Motion etc.

Important Questions on Collisions

HARD
IMPORTANT

Two towers AB and CD are situated a distance d apart as shown in figure. AB is 20 m high and CD is 30 m high from the ground. An object of mass m is thrown from the top of AB horizontally with a velocity of 10 ms1  towards CD. Simultaneously another object of mass 2m is thrown from the top of CD at an angle of 60° to the horizontal towards AB with the same magnitude of initial velocity as that of the first object. The two objects move in the same vertical plane, collide in mid-air and stick to each other. Find the position where the objects hit the ground (from B).

Question Image

MEDIUM
IMPORTANT

A small block of mass M moves on a frictionless surface of an inclined plane, as shown in the figure. The angle of the incline suddenly changes from 60 to 30at point B. The block is initially at rest at A. Assume that collisions between the block and incline are totally inelastic. g=10 m/s2Question Image

If the collision between the block and the incline is completely elastic, then the vertical (upward) component of the velocity of the block at point B, immediately after it strikes the second incline is:

MEDIUM
IMPORTANT

A block of mass 0.50 kg is moving with a speed of 2.00 m s-1 on a smooth surface. It strikes another mass of 1.00 kg and then they move together as a single body. The energy loss during the collision is:

MEDIUM
IMPORTANT

Two small particles of equal masses start moving in opposite directions from a point A in a horizontal circular orbit. Their tangential velocities are v and  2 v, respectively, as shown in the figure. Between collisions, the particles move with constant speeds. After making how many collisions, other than that at A, these two particles will again reach the point A?

Question Image

MEDIUM
IMPORTANT

A smooth sphere A is moving on a frictionless horizontal plane with angular speed ω and centre-of- mass velocity v. It collides elastically and head-on with an identical sphere B at rest. Neglect friction everywhere. After collision, their angular speeds are ωA and ωB respectively. Then:

MEDIUM
IMPORTANT

Consider a rubber ball freely falling from a high height  h = 4.9 m on to a horizontal elastic plate. Assume that the duration of collision is negligible and the collision with the plate is totally elastic. Then the velocity as a function of time and the height as a function of time will be:

HARD
IMPORTANT

Two particles of masses m1 and m2, in projectile motions, have velocities v1<v2 respectively at t=0. They collide at time t0. The velocities become v1 and v2 at time 2t0 while moving in air. The value of m1v1+m2v2m1v1+m2v2 is

HARD
IMPORTANT

A point mass of 1 kg collides elastically with a stationary point mass of 5 kg. After their collision, the 1 kg mass reverses its direction and moves with a speed of 2 m s-1. Which of the following statements is correct for a system of these two masses?

EASY
IMPORTANT

Two objects of the same mass and with the same initial speed, moving in a horizontal plane, collide and move away together at half their initial speeds after the collision. The angle between the initial velocities of the objects is,

EASY
IMPORTANT

Two masses m and 2m are placed in a fixed horizontal circular smooth hollow tube as shown. The mass m is moving with speed u and the mass 2m is stationary. After their first collision, the time elapsed for next collision is (Coefficient of restitution is, e=12)

Question Image

HARD
IMPORTANT

A particle of mass m1 and velocity vi collides head-on with a stationary particle of mass m2. After collision the velocity of both particles is vj. The energy lost in the collision is:

HARD
IMPORTANT

A proton of mass 1 a.m.u. collides with a Carbon-12 nucleus (mass = 12 a.m.u.) at rest. Assuming that the collision is perfectly elastic and that the Newton's laws of motion hold, what fraction of the proton's kinetic energy is transferred to the Carbon nucleus ?

EASY
IMPORTANT

Two identical spheres P and Q lie on a smooth horizontal circular groove at opposite ends of a diameter. P is projected along the groove and at the end of time t, impinges on Q. If e is the coefficient of restitution, then the second impact will occur after the shortest time of

MEDIUM
IMPORTANT

A tennis ball is released from height h above ground level. If the ball makes inelastic collision with the ground, to what height will it rise after the third collision, e is the coefficient restitution between ball and ground?

EASY
IMPORTANT

A body of mass m1 moving with an unknown velocity of v1 i^,  undergoes a collinear collision with a body of mass m2 moving with a velocity v2 i^. After the collision, m1 and m2 move with velocities of v3 i^ and v4 i^, respectively. If m2=0.5 m1 and v3=0.5 v1, then v1 is:

EASY
IMPORTANT

A metal ball falls from a height of 1 m on to a steel plate and jumps up to a height of 81 cm. The coefficient of restitution of the ball and steel plate is

HARD
IMPORTANT

A smooth sphere A is moving on a frictionless horizontal plane with angular speed ω and centre of mass velocity v. It collides elastically and head-on with an identical sphere B at rest. Neglect friction everywhere. After the collision, their angular speeds are ωA and ωB respectively. Then,

EASY
IMPORTANT

When two bodies collide elastically, the force of interaction between them is

HARD
IMPORTANT

Coefficient of restitution during the collision is changed to 12, keeping all other parameters unchanged. What is the velocity of the ball B after the collision?

MEDIUM
IMPORTANT

A sphere having mass m moving with a constant velocity hits another stationary similar sphere. If e is the coefficient of restitution, then ratio of speed of the first sphere to the speed of the second sphere after collision will be: