FREE FCTC Test Mechanical Reasoning Principles Questions and Answers Flashcards

A ball rolls off a horizontal table at 5 ft/s. Ignoring air resistance, what happens to its horizontal velocity as it falls?

Answer: It remains constant

In projectile motion, horizontal velocity remains constant because no horizontal force acts on the object (ignoring air resistance).

Two identical springs are connected in parallel (side by side) and support a load together. Compared to a single spring, the combined stiffness is:

Answer: Double

Springs in parallel add their spring constants, so two identical springs in parallel have twice the stiffness of one spring.

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

Answer: It quadruples

By the continuity equation, when the pipe diameter halves (area quarters), velocity must quadruple to maintain constant flow rate.

A steel block and an aluminum block of the same size are heated equally. Which expands more?

Answer: Aluminum, because it has a higher thermal expansion coefficient

Aluminum has a higher coefficient of thermal expansion than steel, so it expands more for the same temperature increase.

A car engine produces 200 ft-lbs of torque at 3,000 RPM. Which change would produce the greatest increase in output power?

Answer: Doubling the RPM to 6,000 while maintaining torque

Power equals torque times RPM; doubling RPM while maintaining torque doubles the power output, achieving the maximum increase among the options.

A block sits on an inclined surface at 30° and does not slide. Which force prevents it from sliding down?

Answer: Static friction

Static friction is the force that acts between surfaces at rest relative to each other, preventing the block from sliding down the incline.