Energy, work and power — practice question

While riding his bicycle for $2.0\,\text{minutes}$, a boy has an average power output of $60\,\text{W}$. What amount of useful energy does he expend?

• A$0.50\,\text{J}$
• B$30\,\text{J}$
• C$120\,\text{J}$
• D$7200\,\text{J}$