Friction

Friction Worksheet-7

61. Our hands become warm when we rub them. Why?

62. Mention three examples which show that friction produces heat.

63. We observe that in some cases we want to increase friction. Explain why.

64. Why do we need to decrease friction and how it can be decreased?

65. How do wheels reduce friction?

66. What are the factors on which frictional force depends in fluids?

Friction Worksheet-8

1. Define friction.

2. Which is more sliding friction or static friction?

3. What are lubricants?

4. What is rolling friction?

5. Which is greater–rolling friction or sliding friction?

6. What are fluids?

7. Do fluids exert friction?

Friction Worksheet-9

21. Can we have surfaces with zero friction?

22. Which surface have more friction - rough or smooth? Why?

23. Would it be possible to walk easily on wet marble floor? Why?

24. Why is it possible to write on rough black board with chalk?

25. A ball is set rolling on the ground. Will it stop by itself ? Why?

26. Why do the soles of shoes wear out?