Answer:
375J of wasted energy
Step-by-step explanation:
Efficiency=work output/work input×100%
50=w.o/750×100
750×50=100w.o
w.o=750×50/100
w.o=75×5
w.o=375J
Wasted energy=750J-375J
=375J
Aliter
If the machine is 50% efficient then it is also 50% inefficient
50%×750J=375J