Q. 15

# Two blocks of masses 10 kg and 20 kg moving at speeds of 10 m s^{–1} and 20 m s^{–1} respectively in opposite directions, approach each other and collide. If the collision is completely inelastic, find the thermal energy developed in the process.

Answer :

**Given:**

Mass of blocks:10kg and 20kg

Speeds of blocks:10m/s and 20m/s

**Formula used:**

Momentum=mv

M=mass

V=velocity

Conserving momentum

Momentum initial=momentum final

10× 10-20×20=30× final velocity

Final velocity=10m/s

Thermal energy=change in kinetic energi

Thermal energy=3000J

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