Explain how machines can be useful if the output work is always less than the input work. how can machines be useful if the output work is always less than the input work?

Because shotguns bullets ricochet

Aliquid is an answer i hope this

Ke reqd to move from 0 to 50 will be proportional to 50x50 or 2500. this is equal to w.  to change vel from 50 to 150 you need energy prop to 22500 - 2500 = 20,000. this corresponds to 8w.  best answer is a) . work reqd is prop to velocity squared. 

Go to answer choices