Test: Friction - 1 - Class 8 MCQ

We sprinkle powder on carrom board to make the surface of the board smooth. This reduces the friction between the surface of the carrom board, the striker and the coins. As a result, the coins and the striker can move easily on the carrom board.

• Friction comes into play when irregularities present in the surfaces of two objects in contact get interlocked with each other.
• In sliding, the time given for interlocking is very small. Hence, the interlocking is not strong.
• Therefore, less force is required to overcome this interlocking. Because of this reason, sliding friction is less than static friction.

- A spring balance is used for measuring weight.
- Weight is the force exerted by gravity on an object.
- A spring balance measures this force by the extension of a spring.
- The unit of measurement is typically newtons (N).
- Although weight depends on mass, weight varies with the gravitational field, while mass remains constant.
- Therefore, a spring balance effectively measures the gravitational force (weight) acting on an object, not its mass.

Friction is caused by the irregularities on the two surfaces in contact. This means that when two things are touching each other, the bumps and rough parts on their surfaces stick together, making it harder to move them against each other. So, the correct answer is "Surfaces."

• When we push or pull an object, friction acts in the opposite direction to the motion.
• So, if we push a book to the right, friction acts to the left, and if we push it to the left, friction acts to the right.
• This means friction opposes the motion, trying to stop the object from moving.
• So, the statement is False.

Friction opposes the relative motion between two surfaces in contact. Frictional force acts in opposite direction of motion to slow down the speed of moving body.

Fluid friction can be minimized by giving suitable shapes to the objects moving in the fluids.

A polished marble surface has the least frictional force, hence a car will travel farther on a marble floor.

In machine, friction between moving parts is reduced by using lubricants. These lubricants stick with machine parts to make them smoother that leads to reduction in friction.

Friction always acts in the opposite direction to the motion, hence the force of friction will be from left to right.

When objects move through fluids like air or water, they experience a force called frictional force. This force makes it harder for objects to move smoothly through the fluid.