E/V = w (v2 − v1) / g;
and consequently
v2 − v1 = gE / Vw
(73)
The ratio of this fluctuation to the mean velocity, sometimes called the unsteadiness of the motion of the body, is
(v2 − v1) V = gE / V2w.
(74)
§ 118. Actual Energy of a Shifting Body.—The energy which must be exerted on a body of the weight w, to accelerate it from a state of rest up to a given velocity of translation v, and the equal amount of work which that body is capable of performing by overcoming resistance while being retarded from the same velocity of translation v to a state of rest, is
wv2 / 2g.