Answer
69.2 W
Work Step by Step
Rate of ATP usage = $5 \times 10^{13} \times 10^{9}$ = $5 \times 10^{22}$ molecules/min
$(5 \times 10^{22}) \div 60$ = $8.33 \times 10^{20}$ molecules/second
$(8.33 \times 10^{20}) \div (6.02 \times 10^{23}) = 1.38 \times 10^{-3}$ mol/second
Energy released = $1.38 \times 10^{-3} \times 50$ = $6.92 \times 10^{-2}$ kJ/sec = 69.2 J/sec = 69.2 W
