Why does the law of conservation of energy limits the efficiency of any machine.

Because machines cannot create new energy themselves, they merely change its direction, its form, the amount applied, or the distance it is applied over. Therefore, although it may seem like machines make things easier, in reality they just convert one form of energy into another, and cannot multiply energy or work.

Explanation:

acceleration = (change in speed) / (time for the change)

change in speed = (20-120)= -100 m/s.

1.5 min = 90 sec

acceleration = -100/90 = -1.11 m/s^2.

we don't care about the 150kg or the 2,500 meters. they don't make any difference.

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resonant frequency