Two blocks of masses 10 kg and 20 kg moving
Question:

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

Solution: