Question

question 5 (1 point)
at what rate is a 60.0-kg boy using energy when he runs up a flight of stairs 10.0-m high, in 8.00 s?
75.0 w
735 w
4.80 kw
48 w

Explanation:

Step1: Calculate work done (energy used)

Work done against gravity is \( W = mgh \), where \( m = 60.0\,\text{kg} \), \( g = 9.8\,\text{m/s}^2 \), \( h = 10.0\,\text{m} \).
\( W = 60.0 \times 9.8 \times 10.0 = 5880\,\text{J} \).

Step2: Calculate power (rate of energy use)

Power \( P = \frac{W}{t} \), where \( t = 8.00\,\text{s} \).
\( P = \frac{5880}{8.00} = 735\,\text{W} \).

Answer:

735 W (the option with "735 W")