Applying Mechanical Reasoning Flashcards

An inclined plane is 12 feet long and rises 3 feet. What is its mechanical advantage?

Answer: 4

Mechanical advantage of an inclined plane = length ÷ height = 12 ÷ 3 = 4.

A wheel and axle has a wheel radius of 18 inches and an axle radius of 3 inches. What is its mechanical advantage?

Answer: 6

Mechanical advantage = wheel radius ÷ axle radius = 18 ÷ 3 = 6.

Two pistons in a hydraulic system are connected. The smaller piston moves 10 inches downward. If the area ratio (large/small) is 5:1, how far does the large piston move?

Answer: 2 in

Volume is conserved; with a 5:1 area ratio, the large piston moves 10 ÷ 5 = 2 inches.

A pulley system is fixed to the ceiling (fixed pulley only). What does this arrangement provide?

Answer: Changes the direction of force only

A single fixed pulley only redirects the force — it provides no mechanical advantage, so you still lift with the same force as the load.

Gear A (10 teeth) drives Gear B (30 teeth), which is on the same shaft as Gear C (10 teeth), which drives Gear D (30 teeth). What is the overall gear ratio from A to D?

Answer: 9:1

Each gear pair has a 3:1 ratio; combined in series they multiply: 3 × 3 = 9:1 overall ratio.

A wrench handle is 12 inches long. To loosen a bolt, a mechanic applies 30 lb of force perpendicular to the handle. What torque is applied?

Answer: 30 ft-lb

Torque = force × distance = 30 lb × 1 ft (12 in ÷ 12) = 30 ft-lb.

What is the primary purpose of a flywheel in an engine?

Answer: Store rotational energy to smooth out power strokes

A flywheel stores rotational kinetic energy during power strokes and releases it during non-power strokes to keep rotation smooth.