Question

Using a lever, a person applies 60 newtons of force and moves the lever 1 meter. This moves a 200N rock at the other end by 0.2 meters. Work Output? Work Input? Efficiency?

Answer 1

ANSWER:

Work Output = 40 N*m

Work Input = 60 N*m

Efficiency = 66.67%

STEP-BY-STEP EXPLANATION:

Work Input:

$\begin{gathered} W_{\text{out}}=F\cdot d \\ W_{\text{out}}=60\cdot1=60\text{ N}\cdot m \end{gathered}$

Work Output:

$\begin{gathered} W_{i\text{n}}=F\cdot d \\ W_{\text{in}}=200\cdot0.2=40\text{ N}\cdot m \end{gathered}$

Efficiency:

$E=\frac{W_{\text{out}}}{W_{\text{ in}}}\cdot100\text{\% }=\frac{40}{60}\cdot100=66.67\text{\%}$