An object initially at rest experiences an acceleration of 1.4 m/s for 5.0 s and then travels at that
constant velocity for another 6.0 s.
Part A
What is the object's average velocity over the 11 s interval?

1.4m/s

Explanation:

Average velocity is the total distance covered divided by the total time taken.

 Average velocity  =  

 Total time taken  = 5s + 6s  = 11s

The first distance covered  = velocity x time  = 1.4 x 5 = 7m

     second distance covered  = velocity x time  = 1.4 x 6  = 8.4m

So;

  Average velocity  =    = 1.4m/s

resonant frequency

one person pulls 90n one way and the other has 100n pulling the other way.

so the net force = 90 - 100 = -10n,

or the ans can be 10n if the picture shows -90n and 100n instead.