Question bank/JEE Main/Physics

JEE MainPhysicsModerateWork Power & Energy

A block is moved very slowly from A to D with the help of a
variable force on block which is always tangential to the surface of the
fixed curve path. Coefficient of friction between block and surface is
µ. (The block always remain in contact with plane). Work done by
friction in this process is

Show answer and solution
Work done by
friction=−∫μmgcosθdl=−∫μmgdx=−3μmgl= - \int\mu mgcos\theta d\mathcal{l = - \int}\mu mgdx = - 3\mu mg\mathcal{l}

Source: Grass-G / P-06 Physics paper 14 October.docx

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