Aparticle starts at the origin and moves away from it in a straight line. after 1.6 seconds it is 12.8 meters from the origin. it then reverses direction due to a force field with a like charge. after 3.8 seconds total , the particle is at -9.23 m what is the average velocity of the particle over 3.8 s?

The force that acted upon the body in for it to begin moving is represented by the equation:
F = ma
where F isis force, m is mass, and a is acceleration.

we know the mass is 4 kg.

we know the speed and the amount of time it took to get that speed. the amount of time it takes to reach a speed is acceleration. the equation for this is
a = (delta v) / t
a is acceleration. delta v is change in velocity. t is time.

So
a =(8 - 0 ) / 2
a = 4

F =4 * 4

F = 16 N