What is the minimum speed needed for a cannonball to orbit the Earth?

[saan100]

1) Graph Fg vs. r
Fg on y-axis, r on x-axis (from 1re to 6re)

re (radius of the Earth)

2) If a cannon ball is fired from the top of Everest parallel to the Earth's surface fast enough (ignoring air resistance and assuming that it doesn't bump into anything), it will "orbit" the Earth and hit the back of the cannon that it was fired from. Find the speed required to do this.

 

[Salamon]

Write down what equation you need for universal gravitation. Then I will help you.