Question

a mass m is left free at a distance 3R from the surface of earth on reaching the surface. what will be its velocity? ​

Answer 1

Answer:

Gravitational potential inside hollow sphere =−

R

GM

Gravitational potential at distance 3R=−

3R

GM

∴ Conservation of energy

⇒

2

1

mv

2

−

R

GMm

=−

3R

GMm

⇒12mv

2

=

R

GMm

(1−

3

1

)

⇒

2

v

2

=

3R

2GM

⇒v

2

=

3R

4GM

v=

3R

4GM

solution