Question

An object having mass 3 kg at rest moves under the action of a forcefor 4s with an acceleration of 2.5m/s2. What is the gain in the momentum of the object?

Answer 1

Answer:= m×a=10×2=20 N

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.