Super ball Acceleration question

[physics_geek]

A 45.0 g Super Ball traveling at 30.0 m/s bounces off a brick wall and rebounds at 17.0 m/s. A high-speed camera records this event. If the ball is in contact with the wall for 4.50 ms, what is the magnitude of the average acceleration of the ball during this time interval? (Note: 1 ms = 10-3 s.)


please explain...i don't get it!

 

[Hootenanny]

As you have been told previously, you must show some effort in solving the question yourself before we can help you.

 

[gutti]

I know everyone doesn't have natural talent in physics but just look at the basics first.

Im 15 doing high school physics and i can get it.

First list data, then see relevant equations should be pretty basic from there.

Always do that with all questions,, list data,, look for equations,, sometimes it also helps to draw diagrams if that makes it clearer for you.

 

[physics_geek]

well i know that the average acceleration equation is the change of velocity/change in time

so i thought it would be

17m/s-30m/s
____________

.0045 s


but i can't seem to get the right answer..i think I am missing something?

 

[ice ace]

velocities are vector quantities.. so 17-(-30) because the ball is changing direction
then divide by the time

 

[gutti]

What is the correct answer?