A skydiver with mass of 60 kg is moving at a constant speed of 20 ms−1 . Rate of work done by gravity is _____. Take g=10 ms−2
Mass of skydiver m=60 kg,
Constant velocity = v = 20 ms−1
Acceleration due to gravity g=10 ms−2
Rate of work done by gravity = work donetime
Force applied by gravity F=mg=60×10=600 N.
Let the skydiver travel x metres in t seconds.
Work done in t seconds = Force × Displacement
So, power =(60×10×x)t
= 60×10× v
= 12000 W
= 12 kW