Solve for r in Circular Motion Problem - Urgent Help Needed

[owura143]

Urgent help needed, please! Circular motion

Suppose the surface (radius = r) of the space station is rotating at 42.7 m/s. What must be the value of r for the astronauts to weigh one-half of their Earth weight?


My soln: Let // represent square root

V = // (GMe/r)

I divided Me by 2 and made r the subject

r = GMe/V^2

but i got the anser wrong

 

[Doc Al]

I presume the problem is talking about the artificial gravity created by a rotating space station--not real gravity. Hint: Consider centripetal acceleration.