AFCT Mechanical Comprehension 3

Question 1

An object weighing 50 pounds is on a frictionless inclined plane at 30 degrees. What force parallel to the plane keeps it stationary?

Accepted Answer

25 pounds

Answer

50 pounds

Answer

43.3 pounds

Answer

35 pounds

Question 2

What is the mechanical advantage of a wheel and axle if the wheel radius is 12 inches and the axle radius is 3 inches?

Accepted Answer

4

Answer

3

Answer

6

Answer

9

Question 3

According to Newton's Third Law, when a rifle is fired, the recoil felt by the shooter is due to:

Accepted Answer

An equal and opposite reaction force

Answer

The bullet's weight

Answer

Air resistance on the bullet

Answer

The gunpowder exploding

Question 4

A block and tackle pulley system has 4 supporting ropes. If the load weighs 200 pounds, what effort is theoretically required?

Accepted Answer

50 pounds

Answer

100 pounds

Answer

25 pounds

Answer

200 pounds

Question 5

Why does a wider base make an object more stable?

Accepted Answer

It keeps the center of gravity over the base more easily

Answer

It reduces the object's weight

Answer

It increases friction with the ground

Answer

It lowers air resistance

Question 6

What type of energy does a compressed spring possess?

Accepted Answer

Elastic potential energy

Answer

Kinetic energy

Answer

Thermal energy

Answer

Chemical energy