Subject :NSO Class : Class 8
In which of the following cases the friction is helpful (H) and troublesome (T)?
(A) Lighting a matchstick
(B) Applying the brakes on a cycle
(C) Use a towel to open tightly closed lid of a bottle
(D) Pulling drawer out of a desk
| (A) | (B) | (C) | (D) | |
| A | T | T | H | H |
| B | H | H | T | T |
| C | T | T | T | H |
| D | H | H | H | T |
Ans 1:
Class : Class 8
Ans 2:
Class : Class 9