Her weight = (mass) · (gravity) = (50kg) · (9.8 m/s²)
Work = (weight) · (height) = (50kg) · (9.8 m/s²) · (6 m)
Power = (work) / (time) = (50kg) · (9.8 m/s²) · (6 m) / (15 s)
Power = (50 · 9.8 · 6 / 15) · (kg · m² / s³)
Power = 196 (kg · m / s²) · (m) / s
Power = 196 Newton-meter/second
<em>Power = 196 watts</em>
Hot air rises<span> because when you </span>heat air<span> (or any other gas for that matter), it expands. When the </span>air<span> expands, it becomes less dense than the </span>air<span>around it. The less dense </span>hot air<span> then floats in the more dense cold </span>air<span> much like wood floats on water because wood is less dense than water.</span>
For an uniformly accelerated motion, we can write

where

is the acceleration of this motion, which in this problem is the gravitational acceleration, with a negative sign because it points downward, against the direction of the motion; h=0.540 m is the distance covered by the flea, and

is the initial velocity.
At the maximum height, the velocity is zero, so

. Therefore we can solve to find

:
Answer: 2. 2.0*10^2 W
Explanation:
Power = Work/Time
Power = (2.0*10^3) Joules/10 seconds
Power = 2.0*10^2 Watts