Question

A body mass 'm' is dropped from height R/2
from earth's surface, where 'R' is the radius of
earth. Its speed when it will hit the earth's
surface is (ve = escape velocity from earth's
surface)​

Answer 1

The escape velocity is defined as the minimum velocity that is needed to go outside the planet earth or any planet.

• The formula for escape velocity consist of G which is universal gravitational constant.
• The mass of the planet or the moon.
• The radius of the  planet.
• Escape velocity=√2(GM)/R
• As given R= R/2 which means
• Escape velocity=√4(GM)/R
• Or =2√GM/R