Mechanical Aptitude Mechanical Aptitude Ultimate 4

Question 1

A lever has its fulcrum 1 foot from a 300 lb load and 3 feet from the effort point. How much effort is required to lift the load?

Accepted Answer

100 lbs

Answer

By the law of levers: Effort × 3 = 300 × 1, so Effort = 300/3 = 100 lbs.

Question 2

What is the function of a flywheel in an engine?

Accepted Answer

To store rotational energy and smooth out power pulses

Answer

A flywheel's mass and rotational inertia store energy during power strokes and release it during compression strokes, smoothing engine output.

Question 3

Which type of bearing is most suitable for heavy radial loads at low speeds?

Accepted Answer

Roller bearing

Answer

Roller bearings have line contact instead of point contact, distributing the load over a larger area and handling heavier radial loads.

Question 4

Air pressure in a sealed container is 30 PSI at 60°F. If the temperature rises to 120°F (in Rankine: 520R to 580R), what is the new pressure?

Accepted Answer

33.5 PSI

Answer

Using Gay-Lussac's Law (P1/T1 = P2/T2 in Rankine): P2 = 30 × (580/520) ≈ 33.5 PSI.

Question 5

A flat washer placed under a bolt head primarily serves to:

Accepted Answer

Distribute the clamping load over a larger area

Answer

A flat washer spreads the bolt's clamping force over a wider surface area, preventing the bolt head from pulling through soft or thin materials.

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