Question

A stone of weight 0.25 kgf is lying on the roof of a building 60 m high.
Calculate the amount of stored energy in the stone. (Take 1 kgf=10 N)

Answer 1

Given :-

Mass of the stone = 0.25 kg

Height of the stone = 60 m

To Find :-

The amount of stored energy in the stone.

Analysis :-

Here we are given with the mass, height and the acceleration due to gravity of the stone.

In order to find the amount of stored energy in the stone substitute the values such that potential energy is equal to mass multiplied to height multiplied to the gravity.

Solution :-

We know that,

• m = Mass
• g = Acceleration due to gravity
• h = Height
• PE = Potential energy

Using the formula,

$\underline{\boxed{\sf Potential \ energy=Mass \times Gravity\times Height }}$

Given that,

Mass (m) = 0.25 kg

Height (h) = 60 m

Gravity (g) = 10 N

Substituting their values,

⇒ PE = mgh

⇒ PE = 0.25 × 10 × 60

⇒ PE = 150 J

Therefore, the amount of stored energy in the stone is 150 J.