Available Answers

1. 1.

   Choose and write the correct answer(MCQs):

   1. The friction force that opposes the surface called:
      1. static friction 
      2. sliding friction
      3. rolling friction
      4. none of these 
   2. Dynamic friction is slightly less than the:
      1. limiting friction
      2. kinetic friction
      3. sliding friction 
      4. rolling friction
   3. Streamlined shape help to reduce:
      1. air friction
      2. water friction
      3. air and water friction
      4. none of these
   4. Friction can be increased by:
      1. polishing
      2. using lubricants
      3. making surface rough
      4. using ball bearing 
2. 2.

   Write T for true or F for false:

   1. Sliding friction is slightly more than the limiting friction.
   2. The spikes on shoes of athletes reduces the friction.
   3. By using the dry surface, friction can be reduced.
   4. The friction between two surfaces decreases with the increase in the weight of a body.
   5. The friction decreases with the increases in the area of contact at the two surfaces.
   6. The conveyer belts are made rough in order to decrease friction.
3. 3.

   Match the column A with column B:

   A	B
   1. Ball bearing	a. decreases friction
   2. Fine powder	b. rolling friction
   3. Streamlined body	c. less friction
   4. Meteor burns	d. sliding friction
   5. One body just slides over another body	e. due to high friction of air

    

4. 4.

   Arrange the following in ascending order of their magnitude: Limiting friction, static friction, sliding friction and rolling friction.

5. 5.

   Give advantages of friction.

6. 6.

   Explain the term:

   Rolling friction and sliding friction.