A tennis ball undergoes an elastic collision when it hits the ...

[gonzo233]

A tennis ball undergoes an elastic collision when it hits the ground and bounces up. It is given that the speed of the ball just before it hits the ground is v0 and immediately after rebounding it is +v0. Which of the statements below is true?
 
  A) The momentum of the ball changes but the momentum of Earth does not.
  B) The momentum of the ball changes and the momentum of Earth also changes by the same amount.
  C) The momentum of the ball does not change but the momentum of Earth changes.
  D) Neither the momentum of the ball nor the momentum of Earth changes.
  E) Additional information is needed to answer this question.

Question 2

An object is thrown upwards with a speed of 14 m/s. How high above the projection point is it after 0.50 s?
 
  A) 0 m
  B) 2.9 m
  C) 5.8 m
  D) 7.0 m
  E) 8.2 m

[cloud]

Answer to Question 1

B

Answer to Question 2

C

[gonzo233]

Thanks for the timely response, appreciate it

[raenoj]

Great answer, keep it coming