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A man weighing 70 kg carries a 30 kg box...

A man weighing 70 kg carries a 30 kg box to the top of a building 20 m high. Calculate the work done by the man (take `g = 9.8 ms^(-2)`).

Text Solution

Verified by Experts

We have
`f _(p) = mu _(s) R = f _(s)`
`mu _(s) = (f _(p ))/( R ) = (f _(s))/( mg) = ( 98 N )/( 20 kg xx 9.8 ms ^(-2))`
`= 0.5`
The angle of friction `theta _(s)` is given by:
`tan theta _(s) = mu _(s) = 0.5`
`theta _(s) = tan ^(-1) (0.5) = 26.6 ^(@)`
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