Friction

Complete the sentence. Friction always ____________

• helps the motion

• opposes the motion

• both of these

• none of these

Which one of these characteristics does a smooth surface has?

• Less frictional force

• More frictional force

• Sometimes less and sometimes more force

• All of above

Friction is a __________

• Contact force

• Non-contact force

• Magnetic force

• None of these

What kind of substances are known as lubricants?

• Increase friction

• Decrease friction

• Increase or decrease friction

• None of these

Fluid are____

• Gases

• Liquids

• Gases and liquids both

• None of these

Fluid are____

• Gases

• Liquids

• Gases and liquids both

• None of these

Rolling friction is smaller than?

• Sliding friction

• Static friction

• Fluid friction

• All of the above

Why are the wheels of vehicles made circular?

• Rolling friction is less than sliding friction.

• As they fit easily in cars

• They have grip

• None of the above

What is the direction of force of friction acting on a moving object?

• Opposite to the direction of moving objects.

• The same direction of the moving objects.

• Both are correct

The frictional force exerted by fluids is called-

• Rolling friction

• Pull

• Drag

• Fluid Force