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JEE PHYSICS MCQ: WORK-ENERGY-POWER
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The bob of a pendulum of mass m and length L is displaced, from the vertical and gently released. In order that the string may not break upon passing through the lowest point, its minimum strength must be
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Correct option: C
3 mg
Option C (3 mg) is correct because at the lowest point, the tension must support both the weight and the centripetal force, which equals 3mg.
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Reason: Angular displacement is not an axial vector. A body of mass thrown vertically upwards attains a maximum height . As what height will its kinetic energy be of its initial value? Assertion: Centripetal force does no work.
Reason: Force and displacement are perpendicular to each other. Statement I: Both stretched and compressed springs possess potential energy.
Statement II: Work done against restoring force is stored as potential energy. A bullet of mass moving at a speed hits a ball of mass kept at rest. A small part having mass breaks from the ball and sticks to the bullet. The remaining ball is found to move at a speed in the direction of the bullet. Find the velocity of the bullet after the collision.