The power of a crane, which lifts a mass of 1000 kg to a height of 20 m in 10 s is: $\left(g=9.8 \mathrm{~m} / \mathrm{s}^2\right)$

Question

Accepted Answer

C. 1. Since the crane lifts the mass against gravity, the work done equals the gain in potential energy, and **power** is work done divided by time taken.

$$P=\frac{W}{t}=\frac{mgh}{t}$$

2. Substitute the given values $m=1000	ext{ kg}$, $g=9.8	ext{ m/s}^2$, $h=20	ext{ m}$, $t=10	ext{ s}$.

$$P=\frac{1000	imes9.8	imes20}{10}$$

3. Simplifying this expression.

$$P=19600	ext{ W}=19.6	ext{ kW}$$

Hence, the answer is **C**.

The power of a crane, which lifts a mass of 1000 kg to a height of 20 m in 10 s is: (g=9.8 m/s2)\left(g=9.8 \mathrm{~m} / \mathrm{s}^2\right)(g=9.8 m/s2)

The power of a crane, which lifts a mass of 1000 kg to a height of 20 m in 10 s is: $\left(g=9.8 \mathrm{~m} / \mathrm{s}^2\right)$