Assessment: Power and Efficiency
Answer every question, then submit to see your score and which topics to review.
Part A β Concept Questions
What does power measure?
EasyWhy can no real machine reach 100% efficiency?
MediumWithin its elastic limit, what happens to a spring's extension if the applied force is doubled?
MediumPart B β Formula & Application
A pump does 24,000 J of work in 8 seconds. Find its power.
MediumA spring with spring constant 200 N/m is stretched by 0.15 m. Find the elastic potential energy stored.
MediumPart C β Problem Solving
A machine is 40% efficient and produces 120 J of useful output. Find the total energy input.
HardA spring stretches 0.04 m under a 60 N force. Find its spring constant.
HardPart D β Real-Life Application
Why is coal considered a non-renewable energy source?
EasyHow does drawing a bow relate to launching an arrow?
MediumPart E β Challenge
A machine is upgraded so that its energy losses to friction are halved, while total input energy stays the same. What happens to its efficiency?
Hard0/10 answered