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 m

Potential 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/s²
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.