CBSE Class 8 Science Friction Assignment Set C

1.When does a body start motion?

2.What is the cause of friction?

3.What is rolling friction?

4.What is sliding friction?

5.What do you mean by the term drag?

6.What is the direction of frictional force?

7.Find the odd one out with reason; Gravitational force, magnetic force, electrostatic force and frictional force.

8.What is force of friction?

9.Explain, how the frictional force is used to stop a moving bicycle?

10.What is the most common way to reduce friction?

(A) Lubrication. (B) Warning signs. (C) Eliminate the motion. (D) None.

11.Do you want to increase or decrease friction when riding a bicycle?

(A) Increase. (B) Both. (C) Decrease. (D) None.

12.Why is it harder to start to slide a heavy box across the floor than to keep it sliding?

(A) Static friction is greater than kinetic friction.

(B) Kinetic friction is greater than the static friction.

(C) Sliding friction is less than rolling friction.

(D) None.

13.What is an advantage of using rollers instead of sliding an object?

(A) Rollers are much less expensive

(B) Rolling friction is much less than sliding friction

(C) Rolling friction has the advantage of being greater than sliding friction.

(D) None

14.Why is it easier to move water through a hose than grease?

(A) Since grease is slippery, it actually moves easier than water.

(B) Water has less viscosity than grease and thus less fluid friction.

(C) Because you would never move grease through a hose in the first place.

(D) None.

15.What effect does surface roughness have on friction?

(A) It is the main reason for friction.

(B) It only has a small effect unless the roughness is extreme.

(C) It depends if the materials are solids or liquids.

(D) None.

16.Friction is:

(A) Always a disadvantage.

(B) Always an advantage.

(C) Sometimes a disadvantage and sometimes an advantage.

(D) Neither an advantage nor a disadvantage.

17.Friction forces act:

(A) In the direction of force applied. (B) In the direction of the motion.

(C) In the direction opposite to the direction of motion. (D) None of these.

18.The effect of frictional force may be minimized by:

(A) Using a smooth object. (B) Using a smooth plane.

(C) Providing a lubricant at the surface of contact. (D) All of these.

19.A car slips on a wet road because

(A) Water increases the friction between the road and the tyres.

(B) It is not possible to apply brakes on a wet road.

(C) The friction between the brakes shoes and the wheels is reduced.

(D)Water reduce the friction between the road and the tyres.

20.Friction force is:

(A) Contact force. (B) Non-Contact force.

(C) Muscular force. (D) None of these.

21.Friction can be reduced by

(A) Polishing. (B) Oiling. (C) By use the ball bearing. (D) All of these.

22.Which force is a contact force:

(A) Magnetic. (B) Electrostatic. (C) Gravitational. (D) Frictional.

23.Rocket has a special streamlined body in order to:

(A) Increase friction. (B) Reduced friction.

(C) Make them attractive. (D) None of these.

24.Grooves in tyre:

(A) Increase friction of the tyre with the road.

(B) Decrease friction of the tyre with the road.

(C) Do not affect friction of the tyre with the road.

(D) Make the tyre look good.

25.Burning of the meteor in the atmosphere is due to:

(A) Electrostatic force. (B) Magnetic force.

(C) Frictional force. (D) Gravitational force.

26.Fluid friction do not depends on:

(A) Speed of object. (B) Shape of object. (C) Nature of the fluid. (D) Speed of the fluid.

27.When an object moves through a liquid, it experiences

(A) Static friction. (B) Sliding friction. (C) Fluid friction. (D) Rolling friction.

28.The force of friction do not depends on:

(A) Material of the object. (B) Wetness of the surface.

(C) Roughness of the surface. (D) Distance of the object from the surface.

29.When one surface attempts to move over another surface, it experiences:

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