JEE Main Physics question
A mass of 20 kg moving with a speed of 10 m/s collides with another stationary mass of 5 kg. As a result, the two masses stick together. The kinetic energy of the composite mass will be [MP PMT 2000]
Answer: (B)
Solution
By momentum conservation: 20(10) + 5(0) = ⟹ = 8 m/s. KE of composite mass = ½(25)(8)² = 800 J.