NFST Mechanical Aptitude 2

Question 1

A lever is used to lift a 200-lb load. If the effort arm is 6 feet and the resistance arm is 2 feet, how much effort force is needed?

Accepted Answer

67 lbs

Answer

Using the lever formula: Effort × Effort Arm = Load × Resistance Arm → Effort = 200 × 2 / 6 ≈ 67 lbs.

Question 2

Which type of pulley system provides the greatest mechanical advantage?

Accepted Answer

A block and tackle with 4 rope segments

Answer

A block and tackle with 4 supporting rope segments provides a mechanical advantage of 4, reducing required effort to one-fourth of the load.

Question 3

What happens to water pressure at the base of a standpipe as the height of water in the pipe increases?

Accepted Answer

Pressure increases

Answer

Water pressure increases with depth; every additional foot of water height adds approximately 0.434 psi to the base pressure.

Question 4

A gear with 40 teeth meshes with a gear with 10 teeth. If the larger gear rotates at 100 RPM, how fast does the smaller gear rotate?

Accepted Answer

400 RPM

Answer

Gear speed ratio is inverse to tooth count: 100 × (40/10) = 400 RPM for the smaller gear.

Question 5

Which of the following best describes the function of a pressure relief valve?

Accepted Answer

It opens to release pressure when a set limit is exceeded

Answer

A pressure relief valve automatically opens to vent excess pressure, protecting the system from damage when pressure exceeds a preset threshold.

NFST Test Practice Test