Answer
Change in the mechanical energy of system caused by the air drag $ =80$ $mJ$
Work Step by Step
$Kinetic$ $energy =\frac{1}{2}mv^{2}$
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 $=80 mJ$
