Question

35
A tennis ball bounces down a flight of stairs
striking each step in turn and rebounding to the
height of the step above. If the height of each step
is d, the coefficient of restitution is
N-
(4) 1
A​

Answer 1

Answer:

The answer will be 1

Explanation:

According to the problem when the ball touches the stairs it rebounding to the height of the step above.

Let the ball is coming from h height and when it going back upwards it is going t up to h height.

When the ball is coming downward it kinetic energy is zero

The potential energy will be = mgh

Now when the ball touches the ground its potential energy will be zero and its kinetic energy is increasing.

Let it will hit the ground with v speed and while coming back it will go with v' speed.

let the  coefficient of restitution is e

Therefore e = v'/v or v'= ev

Now we know v^2 - u^2 = 2gh

while starting u = 0

Therefore h = v^/2g ....(i)

Now while coming back it will be v'^2= 2gh or h = v'^2/2g...(ii)

Therefore,

by diving (i) and (ii)

1 =  v^/2g/ v'^2/2g = v^2/e^2v^2

e= 1

                                     

Answer 2

Explanation: please refer to the attachment. also refer to the diagram in the attachment for better understanding.