Question

An object of mass 100 kg is accelerated uniformly from a velocity of 5 m s–1 to 8 m s–1 in 6 s. Calculate the initial and final momentum of the object. Also, find the magnitude of the force exerted on the object.

Answer 1

Mass of the object, m= 100 kg,
Initial velocity, u= 5 ms-1
Final velocity, v= 8 ms-1
(i) Initial momentum =mu= 100 x 5=500 kg-ms-1
Final momentum = mv = 100 x 8 = 800 kg-ms-1
(ii) From Newton’s second law, Force exerted on the object = Rate of change of momentum
= Change in momentum
= Time Final momentum- Initial momentum
Time = $\frac{800-500}{6}$ =$\frac{300}{6}$= 50N