I think it might be Jupiter—
Solve for "x"
X = speed of the 5 kg
3/15=5/x
cross multiply
3x=75
because (15)(5)=(3)(x)
divide 3 in both side
X=25
or
A=25 m/s^2
Hope this helps
Well, a device that is 100% efficient, would need to accomplish these things: first: it would need no energy to work second: it wouldn't produce any waste third: it would lose no energy while working fourth: it would work forever fifth: it wouldn't need another force (a human, by example) to operate it. according to this, the only thing i think can be called 100% efficient is a natural magnet. it doesn't consume energy (it even produces it) it doesn't produce any waste, and so on. there you go, i'd say a magnet is perfect to use!
