A force that opposes motion between any surfaces that are in contact.

• gravity

• acceleration

• friction

• direction

When an object is moving at constant velocity, the net force acting on it is:

• zero N

• 4 N

• 9.8 N

• 5.25 N

Tags

NGSS.HS-PS2-1

If a bowl is sliding across a table at a constant velocity, the force of kinetic friction (F_k) equals:

• the applied force (F_applied)

• the normal force (F_n)

• the net force (F_net)

• the force of static friction

Tags

NGSS.HS-PS2-1

the force of kinetic friction (F_k) = ?

• the normal force (F_n) multiplied by the coefficient of kinetic friction

• the normal force (F_n) divided by the coefficient of kinetic friction

• the normal force (F_n) multiplied by the coefficient of static friction

• mass x gravity

the normal force (F_n) of a dog sleeping on a couch = ?

• the dog's mass multiplied by the force of gravity

• the couch's mass multiplied by the force of gravity

• the dog's mass divided by the force of gravity

• the couch's mass divided by the force of gravity

Tags

NGSS.HS-PS2-1

A 20 kg minifridge resting on the floor requires a 120 N horizontal force to move it from rest. What is the coefficient of static friction between the minifridge and the floor?

• 0.61

• 0.51

• 0.49

• 0.69

Tags

NGSS.HS-PS2-1

If a 16 kg chair requires a 90 N horizontal force to keep it moving across the floor at a constant velocity, what is the coefficient of kinetic friction between the chair and the floor?

• 0.57

• 0.37

• 0.19

• 0.42

Tags

NGSS.HS-PS2-1

A 75 kg polar bear is sleeping on a frozen lake. What is the normal force of the polar bear?

• 735 N

• 65 N

• 395 N

• 650 N

Tags

NGSS.HS-PS2-1

 What is the unit called that measures force?

• weight
• meter
• Newton
• kilogram

Tags

NGSS.HS-PS2-1

The force that acts in the opposite direction of motion when two surfaces come in contact. 

• Force
• Friction
• Static
• Kinetic