A 600-N box pushed up a ramp that is 2 m high and 5 m long. The person pushing the box exerts a force of 300 N. What is the efficiency of the ramp?

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Borys Shumyatskiy eNotes educator| Certified Educator


The efficiency of a ramp is computed using the notion of mecanical work. It is force multiplied by the displacement, if force and displacement has the same directions.

`W = F*d.`

Our goal is to lift a box on a height, in this case a 600N box 2m high. The work needed for direct lifting is

`600*2=1200` (Joules).

When we use ramp, the force lowers, 300N, but path become longer, 5m. The product is

`300*5=1500` (Joules).

So we make 1500J of work instead of theoretically possible 1200J. The efficiency is

`1200/1500=0.8,` or 80%. This is the answer.

(we use ramp because while losing in work, we can exert lower force. The entire weight may be too great for us)