(1) A player hit a ball in the play ground. The ball stops its own. Explain.
(2) What is rolling friction?
(3) How teachers write on the black board with chalk?
(4)What are lubricants? Give examples.
(5) Which type of foot wear will be good for the old people to save them from slipping?
(6) Why wheel is said to be one of the greatest inventions of mankind?
(7)Fill in the blanks.
(i) The frictional force exerted by fluid is also called ____.
(ii) Ball bearing in wheels _____ friction.
(iii) Friction produces ____.
(8) Explain, why jar of a mixer becomes hot when it is run for a few minutes.
(9) Can we reduce friction to zero by polishing surfaces or using large amount of lubricants?
(10) Imagine that friction suddenly vanishes. How life would be affected. List five such situations.