Question

Std 8
Science worksheet (ch-12]
Q-1 Fill in the blank
1. Friction opposes the
between the surface in contact with each other.
2. Friction depends on the - _of surface.
3. Friction can be reduced by using.
4. The sole of the shoes and tiers of the vehicles are treaded to increase
Q-2 write true or false
1. In many machines friction is reduced by using ball bearing
2. Sliding friction is greater than static friction.
3. Sprinkling of powder on carom board reduced friction.
Q-3 Give answer in short
1. Explain why sportsman use shoes with spikes?
2. Give example to show that friction is both friend and foe.
3. Explain why objects moving in fluid must have special shapes?
4. Why the friction is sometimes undesirable?
0-4Give answer in detail
1. Explain with activity to show factors affecting the friction​

Answer 1

Answer:

(a) Friction opposes the motion between the surfaces in contact with each other.

(b) Friction depends on the nature of surfaces.

(c) Friction produces heat.

(d) Sprinkling of powder on the carrom board reduces friction.

(e) Sliding friction is lesser than the static friction.