Law of Gravitation- Find an expression for the magnitude of the initial velocity that a projectile must possess in order to leave the earth when air friction is neglected.

Question

Law of Gravitation- Find an expression for the magnitude of the initial velocity that a projectile must possess in order to leave the earth when air friction is neglected. 
The gravitational constant for g is, G = 6.67428*10^-11 m^3 Kg^-1 s^-2

Please answer the question fully and please give any helpful websites, thankyou.

Also I know calculus.

bobpursley · Answer

Then set the initial KEnergy equal to the potential energy at the surface of EArth. 1/2 mv^2= GMe*m/re solve for escape velocity, v

Dwayne · Answer

v^2 = 2Mg/r + (u^2 -2Mg/d ) Is that right

bobpursley · Answer

Why did you make it so complicated? 1/2 m v^2=GMe m/re v^2= 2GMe/re take the square root of each side.