Ans. Rolling friction
Ans. They do so to reduce friction in order to increase efficiency.
Ans. Cars, aeroplanes and rockets are streamlined to reduce the fluid friction.
Ans. Frictional force prevents us from slipping every time we take a step forward.
Ans. The treaded tyres of cars, trucks and bulldozers provide better grip with the ground.
Ans. In science, the common name of gases and liquids is fluids. Example: air and water.
Ans. Gymnasts apply some coarse substance on their hands to increase friction for better grip.
Ans. An oily or greasy pole has much less friction due to which it is difficult to climb up an oily or greasy pole.
Ans. The tyres of cars wear out gradually due to friction between the surface of tyres and the surface of road.
Ans. The force required to overcome friction at the instant an object starts moving from rest is a measure of static friction.
Ans. The force required to keep the object moving with the same speed is a measure of sliding friction.
Ans. When one body rolls over the surface of another body, the resistance to its motion is called the rolling friction.
Ans. A well-polished floor offers very less resistance. Therefore, it is difficult to walk properly on a well-polished floor.
Ans. A smooth and wet floor offers very less resistance. Therefore, it is difficult to walk properly on a smooth and wet floor.
Ans. Friction can never be entirely eliminated. No surface is perfectly smooth. Some irregularities are always there.
Ans. Ball bearing is used between hubs and the axles of ceiling fans and bicycles to reduce friction.
Ans. If we rub our hands together for several seconds, then our hands feel warm. That warmth is caused by a force called friction.
Ans. Sportsmen use shoes with spikes because spikes increase the force of friction between the shoes and the ground and give them a better grip while running.
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