Science

Friction

Question:

wet marble floor, dry marble floor, newspaper and towel

Answer:

Force of friction depends on the nature of surfaces in contact. The rougher the surface, the more is the friction between the surfaces in contact and vice-versa. Roughness present in the given surfaces can be arranged in an ascending order as wet marble floor, dry marble floor, newspaper and towel. Hence, the correct sequence of these surfaces when arranged according to the increase in the force of friction acting on the car is—wet marble floor, dry marble floor, newspaper and towel.
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Questions and Answers

Friction

Q 1.

static, sliding, rolling
Answer

Q 2.

wet marble floor, dry marble floor, newspaper and towel
Answer

Q 3.

Suppose your writing desk is tilted a little. A book kept on it starts sliding down. Show the direction of frictional force acting on it.
Answer

Q 4.

Explain why sliding friction is less than static friction.
Answer

Q 5.

Iqbal has to push a lighter box and Seema has to push a similar heavier box on the same floor. Who will have to apply a larger force and why?
Answer

Q 6.

Give examples to show that friction is both a friend and a foe.
Answer

Q 7.

You spill a bucket of soapy water on a marble floor accidentally. Would it make it easier or more difficult for you to walk on the floor? Why?
Answer

Q 8.

Explain why objects moving in fluids must have special shapes.
Answer

Q 9.

Explain why sportsmen use shoes with spikes.
Answer