## Fundamentals of Physics Extended (10th Edition)

Change in the mechanical energy of system caused by the air drag $=80$ $mJ$
$Kinetic$ $energy =\frac{1}{2}mv^{2}$ Substituting the known values and solving, gives: $Kinetic$ $energy = \frac{1}{2}(0.5)4^{2}=4 J$ Potential energy at maximum height is given by: $Potential$ $Energy=mgh$ Substituting the known values and solving, gives: $Potential$ $Energy$ $= 0.5 (9.8)0.8 = 3.92 J$ Change in Mechanical energy $= Kinetic$ $Energy - Potential$ $Energy$ Substituting the values of Kinetic energy and Potential energy gives: Change in Mechanical energy $=4 J-3.92 J= 0.08 J$ So, Change in Mechanical energy $=80 mJ$