Question

The velocity of a body of mass 10kg increases from 4 m/s to 8m/s when force acts on it for two seconds
Find A) what is the momentum of the body before the force acts.
B) what is the gain in momentum per second
C) what is the value of the force

Answer 1

Before the force was applied,
Mass = 10kg
Velocity = 4m/s

Momentum = mass × velocity

=> momentum = 10 × 4 = 40kgm/s

Answer 1 = 40kgm/s

Second question

after force applied,

Mass = 10kg
velocity = 8m/s

Momentum = 10 × 8 = 80kgm/s

This changed in 2 seconds from 40 to 80

Hence, change in momentum =

Final Momentum - initial momentum/time

=>. 80-40/2

=> 40/2

=> 20 kgm/s momentum gained per second


Third question

We can find the acceleration

a = v - u/t

a = 8 - 4/2

a = 4/2

a = 2m/s²

Now we know that

F = ma

hence, F = 10 × 2

F = 20 N


Hope it helps dear friend ☺️✌️✌️