M2.2 Physics - Friction

Which of the following scenarios will likely result in the highest rolling friction?

• A marble rolling on a smooth tile

• A car tire rolling on a sandy road

• A steel ball bearing rolling on a glass surface

If a car is moving at a constant speed on a flat road, what can be said about the frictional force acting on it?

• It is greater than the engine force

• It is equal to the engine force

• It is less than the engine force

• There is no frictional force

Sam is hover boarding down they hall at a constant velocity. Assuming there is friction, which of the following must be true?

• The force applied by the board must be greater than the frictional force

• The frictional force must equal the force applied by the board

• The force applied must equal zero

• There is not enough information

Which object has the most sliding friction acting upon it?

• Object #1

• Object #2

• Object #3

• Objects #1, #2, and #3 have equal sliding friction.

What is the coefficient of kinetic friction if a 20 N force is required to keep a 50 N object moving at a constant speed?

• 0.6

• 0.5

• 0.4

• 0.2

What is the coefficient of static friction if it takes 44 N of force to move a box that weighs 88 N? 

• 0.78
• 0.50

• 0.78 N
• 0.58 N

Which of the following surfaces would likely have the highest coefficient of static friction?

• Polished wood

• Ice

• Wet concrete

• Dry asphalt

If a block is at rest on an slope, which force is primarily responsible for preventing it from sliding down?

• Gravitational force

• Normal force

• Sliding friction

• Static friction

Which type of friction is the strongest? (has the greatest force)

• Kinetic friction (sliding friction)

• Rolling friction

• Static friction

• All forms of friction are equal for the same object.

What is the force of friction acting on a 10 kg object sliding on a surface with a coefficient of kinetic friction of 0.4?

• 4 N

• 10 N

• 40 N

• 0.4 N