A .15kg ball is dropped from a height of 14 m to the ground below, and hits the ground with a speed of 12 m/s.
With what speed would the ball have hit the ground if there were no air resistance?
How much work does the air resistance do on the ball?
no resistance:
Vf=sqrt2gh
work air resistance did?
mgh-1/2 m 12^2=work done on air
Air resistance does not do work, it absorbs energy at best.