Thank you for your help.

Based on the information in the question, can we tell how high the rubber ball will reach after bouncing off the concrete surface?

For question 45,
Part A - Position 1
Part B - Position 4
Part C - I would place my X in between Position 2 and 3.

You are correct to say that we do not really know the height of the rubber ball after bouncing as it is a factor of the material composition of the ball and the surface the ball bounces off of. We know the surface is concrete, which has low elasticity, therefore it will not absorb much of the ball's kinetic energy. So really the height is dependant on the material of the ball (excluding air resistance and temperature). Even though it states rubber, there are many rubber compounds.

So how did I choose between position 2 and 3. There are 4 positions spaced out - that is 25% of the height per position. Most balls (basketball, golf ball, football, etc.) will only achieve a bounce rate of 30-60% by design - baseballs even less.

Where did the kinetic energy go, considering the ball does not bounce all the way back up to position A ?

Chris Rogers wrote:

Where did the kinetic energy go, considering the ball does not bounce all the way back up to position A ?

Hi Chris

Thank you for your reply.

The answer given in the WS is (3).But, I think (2) is also a logical answer, given the information in the question.

Students should understand that KE has been converted into heat and sound energy and the ball will not bounce to its original height.

For PArt C, i would agree with Chris.
Students are actually taught after each bounce, it is about half the distance (not considering the type of ball used, coz that would be beyond their level) So the answer is between 2 and 3. As a matter of fact, when i first read the question, i realise the answer is ambiguous.