My apologies, HallsofIvy is absolutely right. The answer I gave you was incomplete.
The formula calculated the distance from the centre of the Earth to the object, however the question asks for the distance from the surface of the Earth to the object. This means we must subtract the Earth's...
As far as I can tell, I think the problem is that you used the wrong mass in the formula
\mbox{g}=\frac{GM}{r^2}
You used the mass of the weight, but it should be the mass of the earth, which is approximately 5.977\times10^{24} \mbox{ kg}. The equation should be as follows:
5 =...
[SOLVED] Help With Projectiles Problem
Homework Statement
A car rolls down a slope at 30° to the horizontal, and reaches 40 m/s just before plunging off a cliff 180m high. What is its velocity just before hitting the bottom?
Homework Equations
U_H = vcos\theta
U_V = vsin\theta...