⚛️ Physics · Work, Energy and Power · NEET & JEE

A 2 kg ball moving at 4 m/s collides head-on with a 3 kg ball at rest. If the coefficient of restitution is 0.5, the speed of the 3 kg ball after collision is:

Answer: 2.4 m/s.

A 2.4 m/s
B 1.6 m/s
C 0.4 m/s
D 3.0 m/s

Correct answer: A. 2.4 m/s

Explanation: Momentum: 8 = 2v₁ + 3v₂. Restitution: v₂ - v₁ = 0.5×4 = 2. Solving gives v₂ = 2.4 m/s (and v₁ = 0.4 m/s).

As a pendulum swings, total mechanical energy (KE+PE) stays constant: at the highest points A and C, all energy is potential (zero speed); at the lowest point B, all of that energy has converted into kinetic energy (maximum speed).

Concept context

Work-energy theorem, potential energy, conservation of energy, collisions.

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A 2 kg ball moving at 4 m/s collides head-on with a 3 kg ball at rest. If the coefficient of restitution is 0.5, the speed of the 3 kg ball after collision is:

Concept context

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