I’m sure the answer is correct and it is below
“ A catapult works because energy can be converted from one type to another and transferred from one object to another. ... This energy is stored in the launching device as potential, or stored, energy. The catapult you are about to make uses elastic potential energy stored in a wooden stick as you bend it.”
Its safe because it isn't something with electricity
Answer:
a) 
, b) Yes.
Explanation:
a) The maximum thermal efficiency is given by the Carnot's Cycle, whose formula is:
b) The claim of the inventor is possible since real efficiency is lower than maximum thermal efficiency.
Answer:
The turbocharger on a car applies a very similar principle to a piston engine. It uses the exhaust gas to drive a turbine. This spins an air compressor that pushes extra air (and oxygen) into the cylinders, allowing them to burn more fuel each second
Explanation:
