Question

The velocity of a 200 kg object is changed from 5 m/s to 25 m/s in 50 seconds by an applied constant force.

Answer 1

a) Change in momentum is 4000 kg m/s in the direction of motion

b) Magnitude of the force is 80 N

Explanation:

Force is given by rate of change of momentum.

Mass of object = 200 kg

Initial velocity = 5 m/s

Final velocity = 25 m/s

a) Change in momentum = 200 x 25 - 200 x 5

Change in momentum = 4000 kg m/s in the direction of motion

b) Time taken = 50 s

Rate of change of momentum = Change in momentum ÷ Time

Rate of change of momentum = 4000 ÷ 50

Rate of change of momentum = 80 N

Force = 80 N

Magnitude of the force is 80 N