Bennett Mechanical Work and Energy Questions and Answers Flashcards
6 cards from real Bennett Mechanical Test practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 6 Bennett Mechanical Work and Energy Questions and Answers flashcards as text
A machine receives 800 J of input energy but delivers only 600 J of useful work. What is its efficiency?
Answer: 75%
Efficiency = (useful output / input) × 100 = (600 / 800) × 100 = 75%.
Which energy conversion takes place in a hydroelectric dam?
Answer: Gravitational potential to electrical
Water stored at height has gravitational potential energy that converts to kinetic energy, then to electrical energy via turbines.
If the speed of a moving object is doubled, how does its kinetic energy change?
Answer: It quadruples
Since KE = ½mv², doubling velocity increases KE by a factor of 2² = 4 (quadruples).
A 200 N force moves an object 3 m in the direction of the force. How much work is done?
Answer: 600 J
W = F × d = 200 × 3 = 600 J.
Horsepower (hp) is a unit used to measure which physical quantity?
Answer: Power
Horsepower is a unit of power, where 1 hp equals approximately 746 watts.
A roller coaster car at the very top of a hill has its maximum amount of which energy?
Answer: Gravitational potential energy
At the highest point of its path, the car is slowest and has maximum gravitational potential energy.