A 4-kg object, which is moving on a smooth horizontal surface with a velocity of 10 m/s

Question:

A 4-kg object, which is moving on a smooth horizontal surface with a velocity of 10 m/s in the−x-direction, is subjected to a force F_x which varies with time as shown. Approximate the experimental data by the dashed line and determine the velocity of the object

(a) At t = 0.6 s

(b) At t = 0.9 s.