Question

An object is acted upon a force of 10 Newton for 2 seconds if initial momentum was 20 Kg m/s what was the final momentum ​

Answer 1

Explanation:

Correct option is

B

100kg−m/s

Step 1: Acceleration calculation

Applying Newton's second law

∑F=ma

⇒F=ma

⇒10(N)=20(kg) a

⇒a=0.5m/s

2

Step 1: Final speed

Since acceleration is constant,

∴ Applying equation of motion

v=u+at

u= Initial speed =0

v= Final speed

v=0+0.5(m/s

2

)×10(s)

=5m/s

Step 2: Change in momentum ΔP

ΔP=m(v−u)

=20(5−0)kgm/s

=100kgm/s

Hence option B is correct.

Alternate solution

Impulse J=Force×time

=10(N)10(S)

=100NS

Impulse J=ΔP

ΔP=100kgm/s