Uh oh! Wolfram|Alpha doesn't run without JavaScript.
Please enable JavaScript. If you don't know how, you can find instructions
here
.
Once you've done that, refresh this page to start using Wolfram|Alpha.
r''(t)=-G*M/(r(t))^2, r(0)=R, r'(0)=x
Natural Language
Math Input
Extended Keyboard
Examples
Upload
Random
