Question

gray used a pulley to lift a 300 n object a distance of 3 m. it took gray 30 seconds to lift the object. how much power did gray exert?
10 watts
20 watts
30 watts
50 watts

Explanation:

Step1: Calculate work done

Work \(W = F\times d\). Given \(F = 300\space N\) and \(d=3\space m\), so \(W=300\times3 = 900\space J\)

Step2: Calculate power

Power \(P=\frac{W}{t}\). Given \(W = 900\space J\) and \(t = 30\space s\), so \(P=\frac{900}{30}=30\space W\)

Answer:

30 watts