Lee Ben Fardest (esteemed American ski jumper), has a mass of 59.6 kg. He is moving with a speed of 23.4 m/s at a height of 44.6 meters above the ground. Determine the total mechanical energy

Answer 1

He has kinetic energy (E_K) because he is moving and gravitational potential energy (E_GP) because he is elevated above the ground,

E_K = (1/2)mv² where "m" is his mass (in kg), "v" is his velocity or speed (in m/s) and E_K is his kinetic energy (in joules):

E_K = (1/2)(59.6)(23.4)² = 16317 joules

E_GP = mgh where "m" is his mass (in kg), "g" is the acceleration due to gravity which on Earth is about 9.8 m/s², "h" is his height above the ground (in meters), and E_GP is his gravitational potential energy (in joules).

E_GP = (59.6)(9.8)(44.6) = 26050 joules

His total mechanical energy (E_TOTAL) is the sum of these:

E_TOTAL = E_K + E_GP = 16317 + 26050 = 42367 joules but we would round to 3 sig figs to get:

E_TOTAL = 42,400 joules