Question

A force of 20 N acts on a body of mass 8 kg for 5 s, initially at rest. Calculate;
(i) the velocity acquired by the body.
(ii) change in momentum of the body

Answer 1

Explanation:

Force = mass × acceleration

F=10N

m=2kg

then,

a=

m

F

=

2

10

=5m/s

2

(i) Now,

u=0

t=3sec

v=u+at=0+3×5=15m/s

(ii)Initialmomentum=mu=2×0=0

Finalmomentum=mv=2×15=30kg−m/s

Change in momentum=Final momentum - Initial momentum

=30−0=30kg−m/s