Exercises

Alida runs her toy car on a dry marble floor, wet marble floor, newspaper, and towel spread on the floor. The force of friction acting on the car on different surfaces in increasing order will be _____.

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

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?

Explain why sportsmen use shoes with spikes.

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?

Explain why sliding friction is less than static friction.

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

Explain why objects moving in fluids must have special shapes.