Question

Mulhentum
Activity 3
When a force is applied on a body of mass 10 kg for a period of 4 s, the velocity of the body
from 6 m/s to 8 m/s.
changes
What is the rate of change of momentum of the body?
​

Answer 1

Explanation:

Mass of the body =10 kg

Initial velocity u=4 m/s

Final velocity v=8 m/s

Time t=2s

a) Momentum before force acts p

1

=m×u=10×4=40kg.m/s

b) Momentum after force acts p

2

=m×v=10×8=80kg.m/s

c) Gain in momentum per second =

2

40

=20kg.m/s

d) Acceleration a=

t

v−u

=

2

8−4

=2m/s

2

Force =m×a=10×2=20 N

Answer 2

Explanation:

Mass of the body =10 kg

Initial velocity u=4 m/s

Final velocity v=8 m/s

Time t=2s

a) Momentum before force acts p

1

=m×u=10×4=40kg.m/s

b) Momentum after force acts p

2

=m×v=10×8=80kg.m/s

c) Gain in momentum per second =

2

40

=20kg.m/s

d) Acceleration a=

t

v−u

=

2

8−4

=2m/s

2

Force =m×a=10×2=20 N