A particle of mass 1 kg is released from rest at a point where gravitational potential is 5 J/kg. After some time, it passes through a point B with a speed of 1 m/s. What is the gravitational potential at B ?

Explanation

As the particle moves from A to B, its kinetic energy increases.
So, its potential energy at B must be less than its potential energy at A. By conservation of mechanical energy energy we obtain
`K_(A)+U_(A)=K_(B)+U_(B)`
`0+U_(A)=(1)/(2)xx1xx(1)^(2)+U_(B)`
`rArr U_(A)-U_(B)=0.5`
Dividing both sides by mass of the particle
`(U_(A)-U_(B))/(m)=(0.5)/(1)` J/kg.
`rArr V_(A)-V_(B)=0.5` J/kg.
`rArr V_(B)=4.5 J//kg (because V_(A)=5 J//kg)`