Impact of elastic ladies - Advance Level

Impact of elastic ladies - Advance Level

Dear Readers,

Dynamics is the branch of physics developed in classical mechanics concerned with the study of forces and their effects on motion. Isaac Newton was the first to formulate the fundamental physical laws that govern dynamics in classical non-relativistic physics, especially his second law of motion. .

Q1. A ball falls from a height h upon a fixed horizontal plane, e is the coefficient of restitution, the whole distance described by the ball before it comes to rest is

•  (1+e²)h/(1-e²)
•  (1-e²)h/(1-e²)
•  (1-e²)h/(1+e²)
•  None of these

Solution
A ball falls from a height h upon a fixed horizontal plane, e is the coefficient of restitution, the whole distance described by the ball before it comes to rest is (1+e²)h/(1-e²)

Q2.A ball of mass 8 kg and moving with velocity 4 m/sec collides with another ball of mass 10 kg moving with velocity 2 m/sec in the same direction. If the coefficient of restitution is 1/2, the velocities (in m/sec) of the balls after impact are

•  0, 0
•  7/3, 10/3
•  2/3, 5/3
•   2, 2

Solution
If the coefficient of restitution is 1/2, the velocities (in m/sec) of the balls after impact are 7/3, 10/3

Q3.  Three balls of masses m1, m2, m3 are lying in straight line. The first ball is moved with a certain velocity so that it strikes the second ball directly, then the second ball collides with the third. If the coefficient of elasticity for each ball is e and after impact first ball comes to rest, while after second impact the second ball comes to rest. Then m1,m2,m3 are in

•  A.P.,
•  G.P.
•  H.P.
•  None of these

Solution
m1,m2,m3 are in G.P.

Q4. A sphere impings directly on an equal sphere which is at rest. Then the original kinetic energy lost is equal

•  (1+e²)/2 times the initial K.E.
•  (1-e²)/2
•  (1-e²)/2 times the initial K.E.
•  None of these

Solution
Then the original kinetic energy lost is equal (1-e²)/2 times the initial K.E.