4. Study the following activity and
answer the questions.
1. Take two aluminium channels of
different lengths.
2. Place the lower ends of the channels
on the floor and hold their upper
ends at the same height.
3. Now take two balls of the same size
and weight and release them from
the top end of the channels. They
will roll down and cover the same
distance.
Answers
Answer: Law of conservation of energy is demonstrated using this activity. At the top of the channels, the total mechanical energy of the balls is in the form of potential energy. Now, as the roll down, they come into motion. This ,motion shows that the balls now posses kinetic energy. too. As law of conservation of energy states that energy cannot be created nor destroyed, this mean this kinetic energy came into existence because of decreases in potential energy of the ball ( decrease in potential energy is due to decrease in height). Also , when the ball reaches the bottom, the total mechanical energy of the balls in the form of kinetic energy. This shows that all the potential energy of the balls got converted to kinetic energy at the bottom. The potential energy of the balls converts to kinetic energy as they roll down.