A girl of weight 440 N climbs up a rope through a height of 7 m in 20 s. The power expended by the girl is:

Correct option is A

​$$\textbf{Step 1: Power Formula}$$​​

​$$\text{Power } (P) \text{ is given by:}$$ $$P = \frac{\text{Work Done}}{\text{Time}}$$

$$\text{Work done } (W) \text{ is:}$$ $$W = \text{Force} \times \text{Displacement}$$

$$\text{where:}$$

$$\bullet \quad \text{Force } = \text{Weight of the girl } = 440N$$

$$\bullet \quad \text{Displacement } = \text{Height climbed } = 7m$$

$$\bullet \quad \text{Time taken} = 20s$$

$$\textbf{Step 2: Calculate Work Done}$$

$$W = 440 \times 7$$

$$W = 3080 \text{ Joules}$$

$$\textbf{Step 3: Calculate Power}$$

$$P = \frac{3080}{20}$$

$$P = 154W$$​​​​​​​​​​​​​