A ball is dropped from height h on the ground where coefficient of restitution is e. After one balance the maximum height is
Restitution refers to the process of restoring an object to its original state after deformation or impact. In physics it is often used to describe the coefficient of restitution which measures the elasticity of collisions between two bodies indicating how much kinetic energy remains after the collision.
Chapter 5 of Class 11 Physics focuses on Work Energy and Power. Work is defined as the transfer of energy when a force acts on an object. Energy has various forms including kinetic and potential. Power is the rate of doing work and understanding these concepts is vital for analyzing physical systems.
We can find the maximum height reached by a ball after it is dropped from height h and bounces on the ground with a coefficient of restitution e using the following analysis:
1. When the ball is dropped from height h, it gains kinetic energy just before hitting the ground. The potential energy at height h is converted to kinetic energy:
Potential Energy (PE) = mgh
Kinetic Energy (KE) at the moment of impact = mgh
2. When it bounces, some energy is lost due to the coefficient of restitution e. The coefficient of restitution is defined as the ratio of the velocity after the bounce to the velocity before the bounce:
e = (velocity after bounce) / (velocity before bounce)
3. Velocity at the instant of hitting the ground (v) is determined by the relation:
v = √(2gh)
4. Just after the bounce, the velocity is given by,
velocity after bounce = e * v = e * √(2gh)
5. Maximum height (h’) attained just after the bounce can be calculated from the K.E. at the instant of bounce
K.E. after bounce = (1/2) m (e * √(2gh))²
This kinetic energy is turned back into potential energy at the maximum height:
PE at max height = mgh’
Thus, (1/2) m (e² * 2gh) = mgh’
Simplifying gives:
h’ = e²h
Final Answer:
The maximum height after the bounce is e²h.
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