Answer to Question #131759 in Physics for Elvis

Question

3. Describe the energy transformations which occur
i. At a power station which uses coal as its fuel
ii. When a boy shoots a stone from a catapult to hit a target.

Answer 1

The following energy transformation occurs at the power station which uses coal as its fuel: chemical energy of coal turns into thermal energy of fuel. This thermal energy is transmitted to water, which evaporates. The steam, besides thermal energy, acquires mechanical (kinetic) energy, which makes the turbine rotate. In turbine, mechanical energy converts into electrical energy.   

When a boy launches a stone from a catapult to hit a target, the chemical energy of his muscles turns into mechanical energy of their motion. This energy is transmitted to the catapult, which starts acquiring elastic potential energy. When the boy releases the catapult, the elastic potential energy turns into kinetic and potential energy of of the moving part. When the catapult stops, the object that was thrown has a potential and kinetic energy. As the object hits the target, its mechanical energy turns into thermal and mechanical energy of the target.