Posted by Mark on .
An 80 kg man climbs a 50 mhigh hill in 20 minutes. What is the average power in watts he expends climbing the hill?

Physics 
Henry,
F = m*g = 80kg * 9.8N/kg = 784 N.
P = F*d/t = 784 * 50/1200s. = 32.67 J/s
= 32.67 Watts.