C. Answer the following in not more than 100 words.
1. What is energy? Explain with three examples.
2. How are metals and nonmetals used? Give five examples each.
3. Describe how the fundamental particles are arranged in the atom.
Answers
Answer:
1. Energy exists in many different forms. Examples of these are: light energy, heat energy, mechanical energy and gravitational energy.
Answer:
The work-energy principle states that an increase in the kinetic energy of a rigid body is caused by an equal amount of positive work done on the body by the resultant force acting on that body. Conversely, a decrease in kinetic energy is caused by an equal amount of negative work done by the resultant force.
Examples,
(1) A car is accelerating constantly. Here velocity is increasing. As a result of, kinetic energy is also increasing. So positive work is done.
(2) A ball is dropped from a certain height. Here velocity of the ball is increasing gradually due to gravitational acceleration. As a result of which kinetic energy increases and positive work is done.
(3) A motor bike applies break and comes into rest after few second. Here work done by the break is negative. Because speed decreases, for which K.E also decreases
Explanation: