JEE Main Physics Class 11 Work, Energy and Power Part 1 Questions

Given,
Mass of block, m1=1.9 kg
Mass of bullet, m2=0.1 kg
Velocity of bullet, v2=20 m/s
Let v be the velocity of the combined system. It is an inelastic collision.
Using conservation of linear momentum
m1×0+m2×v2=(m1+m2)v
⇒0.1×20=(0.1+1.9)×v
⇒v=1m∕s
Using work energy theorem
Work done = Change in Kinetic energy
Let K be the Kinetic energy of combined system.
(m1+m2)gh
=K−

1

2

(m1+m2)V2
⇒2×g×1=K−

1

2

×2×12 ⇒K=21J