What Is the Average Acceleration of a Super Ball Bouncing Off a Wall?

[Rob21]

Homework Statement

A 50.0 g Super Ball traveling at 30.0 m/s bounces off a brick wall and rebounds at 22.0 m/s. A high-speed camera records this event. If the ball is in contact with the wall for 5.00 ms, what is the magnitude of the average acceleration of the ball during this time interval? (Note: 1 ms = 10-3 s.)

Homework Equations

avg acceleration=(final V-initial V)/change in time

The Attempt at a Solution

(22m/s-30m/s)/0.005s= -1600m/s^2 and since it asks for the magnitude my final answer is
1600m/s^2

This was from my online physics homework. I really don't see what I'm doing wrong.

 

[LowlyPion]

Homework Statement

A 50.0 g Super Ball traveling at 30.0 m/s bounces off a brick wall and rebounds at 22.0 m/s. A high-speed camera records this event. If the ball is in contact with the wall for 5.00 ms, what is the magnitude of the average acceleration of the ball during this time interval? (Note: 1 ms = 10-3 s.)

Homework Equations

avg acceleration=(final V-initial V)/change in time

The Attempt at a Solution

(22m/s-30m/s)/0.005s= -1600m/s^2 and since it asks for the magnitude my final answer is
1600m/s^2

This was from my online physics homework. I really don't see what I'm doing wrong.

I think you need to look at your direction signs more carefully.

Remember velocity is a vector. The sign you assign it needs to be carried through the calculation.