Average kinetic energy hope this helps!
The potential energy of the ball before it falls is (mass) (gravity) (height) =
(0.5 kg) (9.8 m/s²) (4 m) = 19.6 joules
The kinetic energy of the ball when it hits the ground is (1/2) (mass) (speed)² =
(1/2) (0.5 kg) (5 m/s)² = (0.25 kg) (25 m²/s²) = 6.25 joules
a). The <em>energy lost</em> to air resistance during the fall is (19.6J - 6.25J) = <em>13.35 Joules. </em><em>Energy is never destroyed, so these missing joules had to go somewhere. This is the </em><em>work done on the ball by air resistance</em><em> during the fall of the ball.</em>
b). Air resistance worked on the ball all during the fall of 4 meters.
Work = (force) x (distance)
13.35 Joules = (force) x (4 meters)
Divide each side by (4 meters) :
Average force = (13.35 Joules / 4 meters)
<em>Average force = 3.3375 Newtons</em>