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6. Mechanical force is the force generated by __________.
7. __________ force is useful in controlling pollu on by separa ng solid pollutant par cles from the

smoke.
D. Short answer type questions.
Decision-making Skills
1. Define ‘state of motion’ of an object.
2. Give two examples of situations where you push or pull to change the state of motion of objects.
3. What is frictional force?

4. Explain the difference between contact forces and non-contact forces.
5. Why is it easier to slip on a wet surface?
6. Explain the difference between weight and mass.
7. Why do all objects fall towards the Earth?

E. Long answer type questions. Critical Thinking Skills

1. Define force.
2. What is magne c force?
3. Prove that the force of fric on depends on the nature of the two surfaces in contact.
4. Dis nguish between contact forces and non-contact forces with example.

5. Explain how forces are the result of interac on between objects.
6. How can a force change the state of mo on of an object? Provide example from sports like football,
cricket and volleyball.
7. How does a spring balance measure weight and what are its two important features?

Project Ideas Exploration

1. Make a project to show that a liquid exerts pressure. Also prepare a report on it and submit that to
your teacher.
2. Prepare a report on the various ways to reduce fric on. Think of any new material/ technique that
can reduce the fric on. Prepare a report on that.

Life Skills Inference

• Blaise Pascal was a French scien st, inventor and philosopher. He is famous for his study of fluids. He
described how pressure applied to a liquid was transmi ed through the liquid. Find out more about
the life and work of Pascal.

Enhance your Life Skills Mental Development

• Discuss the topic ‘Fric on is a pervasive force’.

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