Question

Question No: 24
24.
Potential energy of an object of mass 'm' at a dis-
tance 3R from the surface of earth is
(R is the radius of earth, g is acceleration due to
gravity on the earth surface)
(1) 0.5 mgR
(2) mgR .
(3) -0.5 mg
(4) -0.25 mgR

Answer 1

Explanation:

Change in P.E.=

(n+1)R

−GMm

−(

R

−GMm

)=(

(n+1)R

GMm

)(−1+(n+1))

=(

R

GMm

)

n+1

(n)

But g=GM/R

2

or GM=gR

2

Putting this value, we get Change in P.E. =mgR(

n+1

n

)

Answer 2

Answer:

1) 0.5mgR

m (mass) and the g(acceleration due to gravity on the earth surface) R(radius of the earth)