A constant force of 5N acts for 5s on a mass of 5kg initially at rest. Calculate the final momentum of the mass.
A
125 kgms-1
B
75 kgms-1
C
25 kgms-1
D
20 kgms-1
E
5 kgms-1
Verified Correct Answer: C.
Physical Principles & Numerical Solution
According to Newton's second law of motion, \(force = \frac{ final momentum - initial momentum}{time}\)
but momentum = mass x velocity; F= 5N, Initial mass = 5kg, time = 5secs, initial velocity = zero
then final momentum = force x time (since initial momentum of the mass = 0, that is 5 x 0)
= 5 x 5 = 25 kgms-1
Source: Myschool Past Questions Archive (Record #42920)