CLASS VIII
WORKSHEET (FRICTION)

I.Fill in the blanks :

1. The force of friction always act in the _____________ direction to the applied force.
2. _____________ comes into play when we try to move an object at rest.
3. _____________ comes into play when an object is sliding over other object.
4. Sliding friction is always _____________ than static friction.
5. Friction can be _____________ by using lubricants.
6. Friction is the force which _____________ the relative motion between two surfaces.
7. Friction can be increased by making a surface _____________.
8. The friction force exerted by fluid is also called _____________.
9. The common name of gases and liquids is _____________.
10. The device used for measuring the force acting on an object _____________.

II. ANSWER THE FOLLOWING QUESTIONS

1.Explain Why, it is easier to drag a mat on floor when nobody is sitting on it but
much more difficult to drag the same mat when a person is sitting on it.
2.Which type of surfaces produce {a} least friction, and {b} too much friction?
3.Out of sliding friction, static friction & rolling friction:
(a) Which one is the smallest?
(b) Which one is the largest?
4. When a pencil cell is released from a certain point on an inclined wooden board, it
travels a distance of 35 cm on floor A before it comes to rest. When the same
pencil cell is released from the same point on the same inclined board, it travels a
distance of 20 cm on floor B before coming to rest. Which floor, A or B, offers
greater friction? Give reason for your answer.
5.A car is moving towards North. What will be the direction of force of friction
acting on this car due to surface of road?