E. Give reasons for the following.
1. A truck is moving with the same speed as a car, the truck has more kinetic energy.
2. A ball resting on the top of a table has more energy than the one lying on the ground
3. Water stored in a dam is used to produce electricity
Answers
Answer:
1. Force×distance= Change in kinetic energy. Both the truck and the car had the same kinetic energy and hence the same amount of work needed to be done. As retarding force applied is same for both, therefore, both the truck and the car travel the same distance before coming to rest.
2. According to Newtons's first law, the body remains in its state unless external force act. This property of body is termed as Inertia. In this given question body is in rest and it is not moving its one because of the inertia Property.
3. To increase the volume of moving water, impoundments or dams are used to collect the water. An opening in the dam uses gravity to drop water down a pipe called a penstock. The moving water causes the turbine to spin, which causes magnets inside a generator to rotate and create electricity.