Question

15.Force of friction depends on

(a) roughness of surface

(b) smoothness of surface

(c) inclination of surface

(d) all of these

16.Force of friction depends on

(a) roughness of surface

(b) weight

(c) size

(d) all of these

17.Fluids are

(a) liquids

(b) gases

(c) both (a) and (b)

(d) none of these

18.Which is a streamlined object?

(a) Boats

(b) Aeroplanes

(c) Ships

(d) All of these

19.Smooth surface has

(a) less friction

(b) more friction

(c) sometimes less and sometimes more

(d) all of these

20.Which of the following is responsible for wearing out of bicycle tyres?

(a) Muscular force

(b) Magnetic force

(c) Frictional force

(d) Electrostatic force

21.It is difficult to walk on an oily floor because

(a) Floor gets spoiled

(b) There is more resistance

(c) Force of friction is high

(d) Force of friction is very less​

Answer 1

Answer:d,a,c,a,c,b

Explanation:

Answer 2

Answer:

15

d

16

a

17

a

18

d

19

a

20

d

21

d