Quizs - The friction force

Which is usually stronger: static friction or sliding friction?

(Ma sát nghỉ hay ma sát trượt thường lớn hơn?)

• Static friction is usually stronger.

• Sliding friction is usually stronger.

• Both are equally strong.

• Static friction is weaker than sliding friction.

Name three types of friction.

• Static friction, sliding friction, and rolling friction.

• Kinetic friction, viscous friction, and magnetic friction.

• Static friction, fluid friction, and thermal friction.

• Sliding friction, elastic friction, and gravitational friction.

When does sliding friction occur?

• It occurs when one object slides over another

• It occurs when two objects are stationary

• It occurs when an object rolls over another

• It occurs when an object is lifted off the ground

Ma sát lăn có nhỏ hơn ma sát trượt không?

• Yes, rolling friction is usually smaller.

• No, rolling friction is larger.

• They are equal.

• It depends on the surface.

A box of mass 10 kg rests on a floor. The coefficient of static friction is 0.4. Find the maximum static friction.

• 29.4 N

• 39.2 N

• 49.0 N

• 19.6 N

What happens if the applied force is less than static friction?

• Vật không chuyển động.

• Vật di chuyển với tốc độ không đổi.

• Vật bắt đầu lăn.

• Vật bị nén lại.

What is the formula for friction force?

• F = μ ⋅ N

• F = m ⋅ a

• F = 1/2 mv²

• F = mgh

Give an example of rolling friction.

• A ball rolling on the floor.

• A car skidding on ice.

• A person sliding down a slide.

• A book sliding off a table.

Lực ma sát là gì?

• It is the force that opposes the motion of an object when it contacts another surface.

• It is the force that accelerates an object in motion.

• It is the force that pulls objects towards the center of the Earth.

• It is the force that allows objects to float on water.

Cho ví dụ về ma sát nghỉ trong đời sống.

• A book resting on a tilted desk without sliding.

• A car skidding on a wet road.

• A person sliding down a slide.

• A ball rolling down a hill.