Purchase Solution

# Average acceleration

Not what you're looking for?

Hi. Here's my problem:

"A tennis ball with a speed of 11.8 m/s is thrown perpendicularly at a wall. After striking the wall, the ball rebounds in the opposite direction with a speed of 8.51 m/s. If the ball is in contact with the wall for 0.00175 s, what is the average acceleration of the ball while it is in contact with the wall? Define the initial direction of the ball's motion to be positive."

I thought I could solve this problem pretty easily using the average acceleration equation (change in velocity divided by time elapsed), but I didn't get the right answer. Here's what I did:

(8.51 m/s - 11.8 m/s) / 0.01175 m/s = -280 m/s^2

Can you tell me what I'm doing wrong here and the correct equation for this problem/the correct way to approach this problem?

Thank you!

##### Solution Preview

Fine!
<br>In such problems use vector method you will never make mistake.
<br>See:
<br>because,
<br>initial velocity = 11.8 m/s (->)
<br>final vlocity = 8.51 m/s (<-)
<br>so if the direction of initial velocity is ...

Solution provided by:
###### Education
• MSc , Pune University, India
• PhD (IP), Pune University, India
###### Recent Feedback
• " In question 2, you incorrectly add in the \$3.00 dividend that was just paid to determine the value of the stock price using the dividend discount model. In question 4 response, it should have also been recognized that dividend discount models are not useful if any of the parameters used in the model are inaccurate. "
• "feedback: fail to recognize the operating cash flow will not begin until the end of year 3."
• "Great thanks"
• "Perfect solution..thank you"

##### Introduction to Nanotechnology/Nanomaterials

This quiz is for any area of science. Test yourself to see what knowledge of nanotechnology you have. This content will also make you familiar with basic concepts of nanotechnology.

##### The Moon

Test your knowledge of moon phases and movement.

##### Variables in Science Experiments

How well do you understand variables? Test your knowledge of independent (manipulated), dependent (responding), and controlled variables with this 10 question quiz.

##### Classical Mechanics

This quiz is designed to test and improve your knowledge on Classical Mechanics.

##### Intro to the Physics Waves

Some short-answer questions involving the basic vocabulary of string, sound, and water waves.