1.   Complete the sentence. Friction always ____________
       a. helps the motion
       b. opposes the motion
       c. both of these
       d. none of these
2.   Which one of these characteristics does a smooth surface has?
       a. Less frictional force
       b. More frictional force
       c. Sometimes less and sometimes more force
       d. All of above
3.   Friction is a __________
       a. Contact force
       b. Non-contact force
       c. Magnetic force
       d. None of these
4.   What kind of substances are known as lubricants
       a. Increase friction
       b. Decrease friction
       c. Increase or decrease friction
       d. None of these
5.   Fluid are____
       a. Gases
       b. Liquids
       c. Gases and liquids both
       d. None of these
6.   On what force of friction depends?
       a. Smoothness of surface
       b. Roughness of surface
       c. Inclination of surface
       d. Al of above
7.   Friction is a /an_______
       a. Evil
       b. Foe
       c. Both (a) and (b)
       d. None
8.   Lubricants ________
       a. Increase friction
       b. Reduce friction
       c. Both (a) and (b)
       d. None
9.   Rolling friction is smaller than?
       a. Sliding friction
       b. Static friction
       c. Fluid friction
       d. All of the above
10.   The shape of the airplane is like a
        a. Bird
        b. Car
        c. Dog
        d. All
1.    B
2.    A
3.    A
4.    B
5.    C
6.    D
7.    C
8.    B
9.    D
10. A