Atennis ball with a speed of 11.3 m/s is moving perpendicular to a wall. after striking the wall, the ball rebounds in the opposite direction with a speed of 7.2207 m/s. if the ball is in contact with the wall for 0.00803 s, what is the average acceleration of the ball while it is in contact with the wall? take "toward the wall" to be the positive direction. answer in units of m/s 2 .

To calculate the average acceleration of the ball we use the formula,

Here, is the final velocity of the ball and is the initial velocity of the ball t is the time in contact with the wall.

Given towards the wall and

away from the wall and .

Substituting these values in above formula , we get

Here is negative because ball is moving away from the wall.

Therefore, average acceleration of the ball is (away from the wall).

the box does not move because you need to use a force greater than 300 n. you are only using 50 n. it needs to at least be 301 n for the box to move because then it is an unbalanced force and it will move the way that the greater force is pushing it. if you use only 300 n it will be a balanced force and will not move because the force you are exerting on the   box is the same as its force.

hope this !

im sorry if i went too in depth, i am going to include a link to a video on khan academy that will explain this.   hope that you like the video and that it explains more in detail to you.

that is the link.