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JAMB Physics 1995 Question 13

Question 13

Friction

Which of the following statements are TRUE about frictional force?
I. It is always a disadvantage
II. It is sometimes a disadvantage
III. It always exists where there is a relative motion of two bodies that are in contact
IV. It is sometimes very useful.

  1. A.I and III only
  2. B.I and IV only
  3. C.II and III only
  4. D.II and IV only
Show the answer and explanation

Answer: D (II and IV only)

Explanation

Friction causes wear and wastes energy (a disadvantage sometimes) but also lets us walk, brake and grip (useful sometimes). So II and IV are true.