Mechanical Reasoning Concepts Flashcards

A hydraulic press has an input piston with area 2 cm² and an output piston with area 20 cm². If you apply 50 N to the input, what force does the output produce?

Answer: 500 N

Pascal's law: output force = input force × (output area / input area) = 50 × (20/2) = 500 N.

Two gears mesh together. Gear A has 10 teeth and Gear B has 40 teeth. If Gear A rotates at 200 RPM, how fast does Gear B rotate?

Answer: 50 RPM

Gear speed ratio is inverse to tooth ratio: Gear B = 200 × (10/40) = 50 RPM.

A block rests on a ramp inclined at 30°. Compared to lifting it straight up, the ramp requires approximately how much force (ignoring friction)?

Answer: Half the force

An inclined plane reduces required force by sin(angle); sin(30°) = 0.5, so half the force is needed.

Water flows through a pipe that narrows from a 4-inch diameter to a 2-inch diameter. What happens to the water's velocity in the narrow section?

Answer: It quadruples

By the continuity equation, velocity × cross-sectional area is constant; area drops by factor 4, so velocity quadruples.

A spring with a spring constant of 200 N/m is compressed by 0.05 m. How much elastic potential energy is stored?

Answer: 0.25 J

Elastic PE = ½kx² = ½ × 200 × (0.05)² = 0.25 J.

A wrench 30 cm long applies 60 N·m of torque to a bolt. What force is being applied to the end of the wrench?

Answer: 200 N

Torque = force × lever arm; force = torque / arm = 60 / 0.30 = 200 N.

A pulley system uses a single movable pulley. What is the mechanical advantage?

Answer: 2

A single movable pulley provides a mechanical advantage of 2 because two rope segments support the load.