To mop-clean a floor, a cleaning machine presses a circular mop of radius R vertically down with a total force F and rotates it with a constant angular speed about its axis. If the force F is distribu

Question

To mop-clean a floor, a cleaning machine presses a circular mop of radius $R$ vertically down with a total force $F$ and rotates it with a constant angular speed about its axis. If the force $F$ is distributed uniformly over the mop and if coefficient of friction between the mop and the floor is $μ,$ the torque, applied by the machine on the mop is:

Question diagram: To mop-clean a floor, a cleaning machine presses a circular

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Answer:

A

Solution:

Net torque $= \sum T o r q u e o n r i n g$

$\int d τ = \int_{0}^{R} μ \times (\frac{F}{π R^{2}} \times 2 π x d x) x$
$τ = \frac{2 μ}{3} F R$

TestHub · Accepted Answer

Net torque = ∑ T o r q u e o n r i n g ∫ d τ = ∫ 0 R μ × F π R 2 × 2 π x d x x τ = 2 μ 3 F R

Physics - Rotation Question with Solution | TestHub

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