An object whose weight is 100lbf( pound force) experiences a decrease i kinetic energy of 500ft-lb, and an increase in potential energy of 1500ft-lbf. The initial velocity and elevation of the object, each relative to the surface of the Earth are 40ft/s and 30ft.
(a). Find final velocity in ft/s . (b) find final elevation.

A. 43.84 ft/s.

B. 45 ft.

Explanation:

A.

Given:

Weight, W = 100 lbf

mass, M = 100/32.174

= 3.108 lb

kinetic energy, ΔKE = -500 ft.lbf

Potential energy ΔPE= 1500 ft.lbf

initial velocity, u  = 40 ft/s

initial height, h1 = 30 ft/s

acceleration, g = 32.174 ft/s^2

ΔKE = 1/2 * M * (v^2 - u^2)

-500 = 1/2 * 3.108 * (v^2 - 40^2)

v = 43.84 ft/s.

B.

ΔPE = M * g * (h2 - h1)

1500 = 3.108 * 32.174 * (h2 - 30)

h2 = 45 ft.

he kicked it 10 feet straight up into the air? i think this works.

like poles repel so keep pushing north to north and repels funny to see this