Static and Kinetic Friction

When the normal force is increased, the force of friction...

• Increases

• Decreases

• Stays the Same

• Depends on the mass of the object

Weight=100N, Force_friction=20N

• μ=5.0

• μ=0.2

• μ=1.2

• μ=0.1

Which is not a way to reduce friction?

• Add more force

• Add oil or another type of lubricant

• Replace rolling with sliding

• Smooth the surface

Why does static friction exists?

• Because surfaces are smoother when you move an object

• Because surfaces are smoother before you move an object

• Because surfaces have imperfections and adhesion occurs between the two

  stationary surfaces

• Because surfaces have imperfections but adhesion does not occur between the two

  stationary surfaces

Which of the following statements is TRUE?

• Static friction results when moving objects or rough surfaces rub together.

• Static friction occurs in a swimmer swimming in water or a boat travelling in water.

• Static friction occurs between two objects that are in motion against each other.

• Static friction occurs when two objects rub against each other or slide against.

Justine places the pile of books on the table. What friction is being shown?

• fluid friction

• static friction

• rolling friction

• sliding friction

Which of the following is an example of static friction?

• Rubbing both hands with each other

• Feet against the ground when walking

• The wheels of a bicycle against the ground

• A heavy box against the ground that difficult to lift and move

Which of the following is/are true about frictional force?

• I only    

• II only  

• I and II     

• II and III

Tags

NGSS.MS-PS2-2

Which of the following exhibits kinetic friction?

• book on the table  

• ball rolling on the floor

• chair folded on the floor      

• man waiting in line at the cashier

Tags

NGSS.MS-PS3-1

NGSS.MS-PS3-5

What are 2 factors that determine the amount of friction between 2 objects?

• Force and roughness between surfaces

• hills and valleys and how smooth or rough the surface is

• Amount of force and amount of surface the comes in contact

• The force and the weight exerted on the surfaces