Question

so to get the initial horizon velocity in order to make it keep orbiting the earth regardless of other force except gravity:

Answer 1

g=mv²/r
sqrt(g*r)=v

is that the velocity ?

Answer 2

mg is an approximation of the gravitational force near the earth's surface. In reality,
\[F_g = G\frac{Mm}{r^2} \]
Though since I'm not sure what you're asking, I'm not sure if that answers your question...

Answer 3

yes, in your equation v = velocity

Answer 4

i am making a model, object move base on x and y coordinate system. Gravity = 0.98, resvx = horizontal velocity, resvy = vertical velocity resax=horizontal acceleration and resay = vertical accleration.

to make the object move i use this code:

x +=resvx

to make it acclerate, i use this code:
x+=resvx
resvx+=resax

that apply on y too.

but the result came out is the bullet was moving circularly around the earth and the radius getting bigger and off the view.

i will try to publish that thing out

Answer 5

You're trying to simulate orbital motion?

Answer 6

i am not sure that your equation is corect

Answer 7

The force of gravity is not constant, first of all...

Answer 8

it is jsut a simple game base , the coordinate system is a bit weird, the y axis is grom up to down. "p" to slow it down or make it fast again. "spacebar" to take snapshot, "r" for restart game. click the green box to shoot the bullet. The variable 'r' mean radius, only updated as the bullet is created. What is the bug cause my bullet fly off the earth??

Answer 9

sorry i posted the old one, here the newer which print more info