# You are atop a 530 foot tall building and hurl a rock upward at a velocity of 40 ft/sec. What is the velocity when it hits the ground?

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- MyRankLv 62 weeks ago
Given,

Height (h) = 530 footInitial velocity (u) = 40ft/secFinal velocity (v) = ?Acceleration due to gravity (g) = 32.18ft/sec²Using kinematic relation:-v² = u² + 2gh→ v = √u² + 2gh= √(40ft/sec)² + 2 x 32.18ft/sec² x 530ft= √1600 + 34110.8 = 188.97 ft/sec∴ final velocity (v) = 188.97 ft/sec.

Source(s): http://myrank.co.in/ - Andrew SmithLv 74 weeks ago
It doesn't hit the ground. It falls back down and lands on the top of the building next to your feet with a speed of 40 feet per second.

Try it yourself and see what happens.

- oubaasLv 74 weeks ago
energy conservation shall apply : m*Vo^2+2*m*g*h = m*Vf^2

Vf = √Vo^2+2gh = √40^2+2*530*32.2 = 189.0 ft/sec

The other comment I was going to make is the velocity when it hits the ground is zero. It had a velocity just PRIOR to hitting the ground. Precision in language has a place.

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hahaha.....arms can be extended outside