Question

A ball having a mass of 0.20 kilograms is placed at a height of 3.25 meters. If it is dropped from this height, what will be the kinetic energy of the ball when it reaches 1.5 meters above the ground?

Answer 1

EC_1 + EP_1 = EC2 + EP_2

EC_2 = 0

EC_2 = EP_1 - EP_2

EC_2 = mg(H_1 - H_2) = 0.20 kg * 9.8 m/s^2 * (3.25 m - 1.5m) = 3.43 J

Answer 2

Answer:

3.43 J

Explanation:

One form of energy can convert to another but cannot be created or destroyed.

A body has potential energy due to its position or configuration.

P.E. = m g h

A body has kinetic energy due to its motion.

K.E. = 0.5 mv²

Mechanical energy is the sum of potential energy and kinetic energy and in the absence of any external forces, the mechanical energy remains conserved.

Potential energy+ Kinetic energy (at the top) = Potential energy +kinetic energy (at 3.25 m)

⇒ m g h + 0 = m g h' + K.E.'

⇒K.E. ' = mg (h -h') = 0.20 kg × 9.81 m/s² × (3.25 m - 1.5 m) = 3.43 J