a body of mass 25kg is raised to the top of a building 10m high and then dropped freely under gravity (g= 10m/s2)

a) calculate the work done in raising the body to the top of the building.

b) what is the value of the gravitational potential energy at the top of the building.

c) by what factor will the gravitational potential energy of the same body increase if it is raised to the top of a multistorey building of 30m high

Potential energy at a height10 m is,

P.E.(10) = mgh = 25×10×10 = 2500 J ...(i)

Work done = P.E of the body = 2500 J

Gravitational potential energy at height h = 30 m is

P.E.(30) = mgh = 25×30×10 = 7500 J ....(ii)

Fron (i) and (ii),

P.E.(30)/P.E.(10) = 7500/2500 = 3

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