What do you mean by conservation of mechanical energy? State the condition when it holds.

Give one example to show that the sum of potential energy and kinetic energy remains constant if friction is ignored.

A truck starts from rest on a plane road. What are the possible energy changes taking place while the truck is in motion?

Read the clues across and clues downwards and fill up the blank squares.

Across :

3. When you burn a coil, the energy released …………… .
4. Door bell converts electrical energy into …………… energy.
5. Windmill converts mechanical energy into …………… energy.
6. The energy stored in food items …………… .

Down :

1. In electromagnet, electrical energy converts into …………… energy.
2. Arrow on a stretched bow possesses …………… energy.
3. A stretched rubber band has …………… energy.
4. The energy stored in atoms is …………… energy.
5. In photosynthesis we require …………… energy.