Question

1. explain how friction affects mechanical energy.
2. how much energy does a 5w light bulb convert to radiant (light) energy and thermal energy in 60s?
3. a boy transfers 500j of chemical energy to mechanical energy to push a box. if it took him 20s to move the box. what was the boys power?

Explanation:

Step1: Recall power formula

Power \( P=\frac{W}{t} \), where \( W \) is work (energy transferred) and \( t \) is time.

Step2: Substitute values

Given \( W = 500J \) and \( t=20s \), then \( P=\frac{500}{20} \).

Step3: Calculate

\( P = 25W \).

Answer:

\( 25W \)