Mechanical Comprehension Questions and Answers Flashcards

If a lever has a 4-foot effort arm and a 1-foot resistance arm, what is the mechanical advantage?

Answer: 4

Mechanical advantage of a lever = effort arm length / resistance arm length = 4 / 1 = 4. A force applied at 4 feet can lift 4 times the load at 1 foot.

A gear with 10 teeth drives a gear with 40 teeth. What is the gear ratio and what happens to speed?

Answer: Gear ratio 1:4; the driven gear spins 4 times slower

Gear ratio = teeth on driven gear / teeth on driving gear = 40/10 = 4:1, so the driven gear rotates at 1/4 the speed of the driver, but torque is multiplied by 4.

Which type of pulley system provides a mechanical advantage of 2?

Answer: A single movable pulley

A single movable pulley provides a mechanical advantage of 2 because the load is supported by two rope segments, halving the effort required.

What is the relationship between pressure and volume in a gas at constant temperature (Boyle's Law)?

Answer: Pressure and volume are inversely proportional — as one increases, the other decreases

Boyle's Law states that at constant temperature, the pressure of a gas is inversely proportional to its volume (P₁V₁ = P₂V₂). Compress a gas and its pressure rises.

A hydraulic system has a small piston with area 2 in² and a large piston with area 20 in². What force does the large piston exert when 10 lbs is applied to the small piston?

Answer: 100 lb

By Pascal's Principle, pressure is transmitted equally. P = F/A = 10/2 = 5 psi. Force on large piston = P × A = 5 × 20 = 100 lb.

What is the purpose of a torque wrench?

Answer: To measure and limit the rotational force applied to a fastener to a specified value

A torque wrench measures and limits the rotational force (torque) applied to a fastener, ensuring it is tightened to the manufacturer's specified value — not too loose or too tight.