posted by Anonymous .
A 50.7 kg student climbs a 6.35 m long rope and stops at the top. What must her average speed be in order to match the power output of a 130 W lightbulb
m g h = gain in potential energy
50.7 * 9.81 * 6.35 = 3158 Joules
joules/t = power
power in Joules/second or Watts = 3158/t
3158/t = 130
t = 24.3 seconds