Which of the following scenarios best illustrates the principle of conservation of momentum?
When a bullet is fired from a gun, the gun recoils in the opposite direction.
When a bullet is fired from a gun, the gun recoils in the opposite direction. is correct.
The law of conservation of momentum states that the total momentum of a system remains constant when no external force acts on it.
Before firing, the gun and bullet are at rest, so total momentum is zero. After firing, the bullet moves forward with momentum \(m_b v_b\), so the gun must move backward with equal momentum: \(m_b v_b + m_g v_g = 0\), giving \(v_g = -\dfrac{m_b v_b}{m_g}\). This backward motion is the recoil.
A ball speeding up on an incline shows gravity doing work (energy conversion); a car stopping by braking involves an external friction force; a satellite in orbit illustrates gravitation providing centripetal force. Only the recoil of the gun directly shows conservation of momentum.
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Which of the following scenarios best illustrates the principle of conservation of momentum?
Important Questions from Laws of Motion
Which of the following is correct?
I. The mass of an object is a measure of its inertia
II. In an isolated system the total momentum remains conserved
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