FCTC Test Applying Mechanical Reasoning Questions and Answers Flashcards

A hydraulic jack has an input piston with an area of 2 square inches and an output piston with an area of 20 square inches. If you apply 100 lbs of force, how much force is exerted on the output piston?

Answer: 1,000 lbs

Hydraulic mechanical advantage equals the ratio of piston areas; 100 lbs × (20/2) = 1,000 lbs of output force.

An electric circuit has a 12-volt battery and a resistance of 4 ohms. What is the current flowing through the circuit?

Answer: 3 amps

Using Ohm's Law, current = voltage ÷ resistance = 12V ÷ 4Ω = 3 amps.

If a bolt has a coarse thread (fewer threads per inch), how does it compare to a fine-threaded bolt of the same size when turned one full revolution?

Answer: It advances more distance

Coarse threads have a larger pitch (distance between threads), so each full revolution advances the bolt a greater linear distance than fine threads.

A spring is compressed by 3 inches with 30 lbs of force. How much force is needed to compress it 5 inches?

Answer: 50 lbs

By Hooke's Law, force is proportional to displacement; the spring constant is 10 lbs/inch, so 5 inches requires 50 lbs.

A block-and-tackle system has 4 rope segments supporting the load. If the load weighs 200 lbs, how much pulling force is required (ignoring friction)?

Answer: 50 lbs

With 4 supporting rope segments, the mechanical advantage is 4, so required force = 200 ÷ 4 = 50 lbs.

Which of the following materials is the best conductor of electricity?

Answer: Copper

Copper has a very low electrical resistance and is widely used as an electrical conductor in wiring.