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A block moves in uniform circular motion...

A block moves in uniform circular motion because a cord tied to the block is anchored at the center of a circle. Is the power of the force exerted on the block by the cord positive, negative, or zero?

Text Solution

Verified by Experts

zero
Explanation: `barF` and `vecv` are perpendicular.
`Power=barF*vecv=Fvcos90^@=Zero`
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Knowledge Check

  • A block of mass m is released from rest at a height R above a horizontal surface. The acceleration due to gravity is g. The block slides along the inside of a frictionless circular hoop of radius R. What is the magnitude of the normal force exerted on the block by the hoop when the block has reached the bottom ?

    A
    mg
    B
    3mg
    C
    `(mg^(2))/(R)`
    D
    2mg

  • Consider a block moving in a horizontal circular path on the inner surface of a cone. The normal force on the block is :

    A
    `mg`
    B
    always greater then mg
    C
    may be greater or less than mg
    D
    always less than mg