Question

Calculate the power of a crane required to lift 36kg of iron per hour from a mine 200 m deep,
(Take g = 10m/s)

Answer 1

m=10

5

kg,g=10ms

−2

,h=360m,t=1h=3600s

The work needed in lifting a mass m to a height h against the force due to gravity is W=mg×h

And, power, P=

t

W

=

t

mgh

∴P=

3600

10

5

×10×360

W=10

5

W=10k