Which of the following option is right if an object fall freely to the ground?

1. The total energy is Kinetic
2. The ratio of potential energy to kinetic energy is constant
3. The sum of potential and kinetic is constant

A. 1 only
B. 2 only
C. 3 only
D. 1 and 2 only

Correct Answer:

Option C – 3 only

Explanation

The total energy at any point combination of the PE and KE

i.e. TEnergy = P.E + K.E

= mgh + ½ mv²

= ½ m (gh + v²)

= ½ m (v² + gh)

∴ TEnergy = ½ m (V² + gh)

∴ Total energy at the height (hm) = P.E + KE

The sum of P.E and KE at any point is always constant .