WTMA Force, Motion, and Friction 2

Question 1

A 10 kg box is pushed across a floor with a force of 50 N while friction exerts 30 N opposing the motion. What is the net force on the box?

Accepted Answer

20 N forward

Answer

Net force equals applied force minus friction: 50 N − 30 N = 20 N in the direction of motion.

Question 2

Which surface combination would produce the HIGHEST coefficient of friction?

Accepted Answer

Rubber on concrete

Answer

Rubber on concrete has a very high coefficient of friction due to the soft, grippy nature of rubber and the rough texture of concrete.

Question 3

A car traveling at 60 mph suddenly brakes. Which force brings the car to a stop?

Accepted Answer

Friction between tires and road

Answer

The friction force between the tires and the road surface is what decelerates the car to a stop.

Question 4

If you double the weight of a box sliding across a floor, what happens to the kinetic friction force?

Accepted Answer

It doubles

Answer

Kinetic friction force equals the coefficient of kinetic friction times the normal force, so doubling the weight (and thus normal force) doubles friction.

Question 5

A ball rolls along a flat surface and gradually slows to a stop. Which force is responsible?

Accepted Answer

Rolling friction

Answer

Rolling friction (or rolling resistance) acts against the motion of a rolling object, causing it to decelerate over time.

WTMA - Wiesen Test of Mechanical Aptitude Practice Test

WTMA - Wiesen Test of Mechanical Aptitude Practice Test

WTMA Force, Motion, and Friction 2