You read in a science magazine that on the moon, the speed of a shell leaving the barrel of a modern tank is enough to put the shell in a circular orbit above the surface of the moon (there is no atmosphere to slow the shell).what should be the speed for this to happen? assume that the radius of the moon is rm = 1.74×10^6m, and the mass of the moon is mm = 7.35×10^22kg.

To solve this problem we will use the definition of the kinematic equations of centrifugal motion, using the constants of the gravitational acceleration of the moon and the radius of this star.

Centrifugal acceleration is determined by

Where,

v = Velocity

r = Radius

From the given data of the moon we know that gravity there is equivalent to

While the radius of the moon is given by

If we rearrange the function to find the speed we will have to

The speed for this to happen is 1.7km/s

e) none of the above answers are correct