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JEE PHYSICS MCQ: WORK-ENERGY-POWER

1 Hard

1 of 1

Application +4 | -1

If potential energy is

U=3 x^2-2 x,

then force will be:

View answer and explanation

Correct option: A

\vec{{F}}=(-6 x+2) \hat{{i}}

Option A (

\vec{{F}}=(-6 x+2) \hat{{i}}

) is correct because force is the negative gradient of the potential energy function.

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A ball throwing cannon, lifts ball and throws with

72 \mathrm{~km} / \mathrm{hr}

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. then find Input power of cannon if it lifts 8 balls per minute and its efficiency is

80 \%

. Mass of each ball is

1 \mathrm{~kg}

. Assertion:When a particle moves in a circle with a uniform speed its acceleration is constant but the velocity changes.
Reason: Angular displacement is not an axial vector. A body of mass

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. As what height will its kinetic energy be

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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

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hits a ball of mass

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kept at rest. A small part having mass

m^{\prime}

breaks from the ball and sticks to the bullet. The remaining ball is found to move at a speed

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in the direction of the bullet. Find the velocity of the bullet after the collision.