Question

A force acts for 0.1 sec on a body of mass 1.2 kg initially at rest . The force than ceases to act and the body moves through 2 m in the next one second . Find the magnitude of the force

Answer 1

Dear Student

Thee are two motions of the body,
i. Force acts for 0.1 s
ii. Force ceases and then moves with constant speed for 1 s.

For ii. There is no force and speed is constant.
v = s/t
v = 2/1 = 2 m/s
This is the final speed.
Now, calculate acceleration for first 0.1 s
a = (v - u)/t
a = (2 - 0)/0.1
a = 20 m/s2

F = ma ( m = 1.2 kg)
F = 1.2 × 20 = 24 N

Regards