Question

10. A particle falls on earth from an unlimited distance. If its initial velocity be zero and the resistance
produced due to friction of air be negligible, then find out its velocity on reaching the earth's surface
Radius of earth is 6400 km and acceleration due to gravity is 9.8 ms
​

Answer 1

2

1

mv

2

−

R

GMm

=0

⇒

2

1

mv

2

=

R

GMm

⇒v=

R

2GM

But GM=gR

2

⇒v=

2gR