When the same masses are heated by the same amount copper will heat up the fastest. Copper is a good conductor of heat that is why it easily heats up. Gold is not a good conductor of heat because of its stable properties.
What are the answer choices, if there are any?
Answer:
<h2>
96 Joules</h2>
Explanation:
We know that efficiency is the ratio of output power by input power. i.e. Efficiency describes the quality of machine or system how good it is.
Solution,
Energy input of system = 120 J
Efficiency = 80% = 
Now,
According to definition,
Efficiency = 
Cross multiplication:

Calculate the product

Hope this helps...
Good luck on your assignment...
This is true. The break handles and brakes are levers and the seat adjustment (raise or lower) is a screw.