Question

If he jumps from the plane with a velocity of +2 ft/s and, after 7 seconds of free fall, he has a velocity of -223ft/s, what is his displacement?

Answer 1

his displacement is 772.85 ft

Step-by-step explanation:

Given;

initial velocity of his jump, u = 2 ft/s

final velocity of his jump, v = - 223 ft/s

time of motion, t = 7 seconds

acceleration due to gravity, g = 32.17 ft/s²

Let downward motion = positive direction

Let his displacement after 7s = Δh

Apply the following kinematic equation to determine his displacement.

`v^2 = u^2 + 2g\Delta h\\\\(-223)^2 = (2)^2 + (2* 32.17)\Delta h\\\\49,729 = 4 + 64.34\Delta h\\\\-64.34 \Delta h = 4 - 49,729\\\\-64.34 \Delta h = -49,725\\\\\Delta h = (49,725)/(64.34) \\\\\Delta h = 772.85 \ ft`

Therefore, his displacement is 772.85 ft