Chapter 7, Problem 69GP

To determine

Height at which it bounces back ,when it reaches the bottom of the stairs.

Answer to Problem 69GP

Ball will get off 4 meters off the ground.

Explanation of Solution

Given:

H (final)= 4.00 m.

Formula used:

  $p=mv$

Calculation:

There will be no loss of energy, so the energy will be conserved. The potential energy after rolling must be same as the potential energy before bouncing up. No forces act in the horizontal direction so the momentum of the ball in this direction is also conserved.

Hence

  $\begin{array}{l}{v}_{initial}=v_{final}\\ \text{So,}\\ h_{initial}=h_{final}=4\text{m}\end{array}$

Conclusion:

  $h_{initial}=h_{final}$ =4.00 m.