question_answer

A man sharpens his knife as shown in the figure. Which of the properties of friction are in use?

(i)  Friction helps us to hold objects.

(ii) Friction acts in the opposite direction of motion.

(iii) Friction causes the surfaces in contact to wear away.

(iv) Friction produces heat energy.

A)  (i) and (ii)

B)  (i), (iii) and (iv)

C)  (iii) and (iv)

D)  All (i), (ii), (iii) and (iv)