Question

need explanation pls
A crane machine is used to lift cement slabs of weight w at Delhi metro site. Machine have to lift the slabs from rest and have to put them on the elevated platform at a height ‘h’. If the maximum tension that the cable of crane machine can tolerate is nw (n > 1), then minimum time in which ascent can be done by the machine is (Tmin = 0)

ANS: (2nh/(n-1)g)^1/2

Answer 1

Answer:

Given that,

The force acting on the crane, F = 5000 N

It is lifted upward to a height of 20 meters, h = 20 m

To find,

The work done by the crane

Solution,

The work done by an object due to height is called its potential energy. It is given by :

E=F\times hE=F×h

E=5000\ N\times 20\ mE=5000 N×20 m

E=10^5\ JE=105 J

So, the work done by the crane is 10^5\ J105 J .

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Work done