Physics-
General
Easy
Question
A planet of radius R has an acceleration due to gravity of gs on its surface. A deep smooth tunnel is dug on this planet, radially inward, to reach a point P located at a distance of 
from the centre of the planet. Assume that the planet has uniform density. The kinetic energy required to be given to a small body of mass m, projected radially outward from P, so that it gains a maximum altitude equal to the thrice the radius of the planet from its surface, is equal to
.
.
The correct answer is:
The gravitational potential at a point Q (OQ º x) is given by :
The energy required to project the body, to a maximum altitude of 3R from its surface, is :
.
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