Question

You machine that tells you exactly how much work in joules is put into a machine and how much work produced. The reading that you just received from the machine state that the input work was 345 joules and the output work was 330 joules. The law of conservation of energy states that input should equal output. How can you explain the "lost" 15 joules

Answer 1

Friction in the machine turned 15 joules of the energy input into heat. If you were monitoring the parts of the machine closely, you would notice that some of them warmed up.