# Potential Energy Numericals Class 9

**Question 1) If acceleration due to gravity is 10 m s ^{-2}, what is the potential energy of a body of mass 1 kg kept at a height of 5 m?**

Solution:

Here, the mass of the body m = 1 kg,

acceleration due to gravity g = 10 m s^{-2}

and, height h = 5 mPotential energy = m g h = 1x10x5 J = 50 J (Answer)

**Question 2) **A bag of wheat weighs 200 kg. To what height should it be raised so that its potential energy is 9800 joule (g = 9.8 m s^{-2})

Solution:

here m = 200 kg

g = 9.8 m/s^{2}

height h = ?

potential energy = 9800 joule

Potential energy = m g h

=> h = Potential energy / (m.g)

=>h= 9800/(200 x 9.8) m = 5 m

Thus, the bag of wheat should be raised to a height of 5m.