Question

An object is thrown straight upwards from the ground at 28 m/s. Due to air resistance (a non-conservative force), the object loses 31.4 percent of its initial energy during its trip to reach maximum height. How much higher does the object travel if there was no air resistance? Answer in meters.

Answer 1

Vo = 28m/s with no air resistance.
h1 = (Vf^2 - Vo^2) / 2g,
h1 = (0 - (28)^2) / -19.6 = 40m.

Vo = 28 * (100%-31.4%)/100% = 18.452m/s
with air res.
h2 = (0 - (18.452)^2) / -19.6 = 17.4m.

h=hi - h2 = 40 - 17.4 = 22.63m. higher
with no air res.