A particle is fired vertically upwards from the surface of earth and reaches a height 6400 km. Find the initial velocity of the particle if R = 6400 km and g at the surface of earth is 10 m//s^(2).

A particle is fired vertically upwards from the surface of earth and r

1.	A particle is fired vertically upwards from the surface of earth and reaches a height 6400 km. Find the initial velocity of the particle if R = 6400 km and g at the surface of earth is 10 m//s^(2).
Answer» Solution :`(1)/(2) mv^(2) = (mgh)/([1+(h//R)])` here h = R = 6400 KM and `G = 10 m//s^(2)` so `v^(2) = gh`, i.e., `v = sqrt(10 xx 6400 xx 10^(3)) = 8 km//s`