Question

A particle of mass 70 g, moving at 50 cm/s, is acted upon by a variable force opposite to its direction of motion. The force F is shown as a function of time t.

(a) Its speed will be 50 cm/s after the force stops acting. 

(b) Its direction of motion will reverse. 

(c) Its average acceleration will be 1 m/s² during the interval in which the force acts. 

(d) Its average acceleration will be 10 m/s² during the interval in which the force acts.

Answer 1

Correct Answer is: (a, b)

The impulse given to the particle is equal to the area under the F–t graph = 0.07 kg m/s = 2 x initial momentum of the particle. Hence, the particle will reverse in direction and move with its initial speed.