KCET 2018 Physics Solved Paper

Gravitational potential energy on surface on Earth is
UE=‌

−GMm

R

where M is mass of Earth; m is mass on surface of Earth; R is radius; G is gravitational constant
When mass m is shifted to a target then potential energy is
U=‌

−GMm

(R+R)

=‌

−GMm

2R

Work done in the process is⇒W=

GMm

2R

Now substitute GM=gR2, we get
W=‌

gR2m

2R

=‌

gRm

2

Therefore, work done in process =

mgR

2