A tennis ball covers a distance of 12 meters in 0.4 seconds what is the velocity of the tennis ball?

30m/s

Explanation:

Given parameters:

Distance  = 12m

Time taken  = 0.4s

Unknown:

Velocity of the tennis ball = ?

Solution:

Velocity of a body is the displacement per unit of time.

  Velocity  =  

So;

      Velocity  =   = 30m/s

0.55x745.7j and a calculator

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.