Question

Workers do 8000 J of work on a 2000-N crate to push it up a ramp. If the ramp is 2 m high, what is the efficiency of the ramp?

Answer 1

Answer:

50%

Explanation:

Efficiency = work out / work in

e = Fd / W

e = (2000 N) (2 m) / (8000 J)

e = 0.5

Answer 2

Answer:

50% efficiency

Explanation:

The efficiency is calculated with the following formula:

$e=\frac{workOut}{workIn}$

this can also be:

$e=\frac{WorkRequired}{WorkDone}$

which is more intuitive for the present problem.

the work required, using the definition of work as $W=F*d$ where $F$ is force in newtons, and $d$ is distance in meters.

$WorkRequired:F*d$

in this case $F=200N$, and $d=2m$, so the work required is:

$WorkRequired:(2000N)*(2m)$

$WorkRequired:4000J$

And the work done according to the problem is:

$WorkDone=8000J$

Thus, the efficiency is:

$e=\frac{WorkRequired}{WorkDone} =\frac{4000J}{8000J} =0.5$

And since $0.5=50$%

⇒the answer is that the efficiency of the ramp is 50%