Tension Force Calculation for George of the Jungle

[hinamori88]

Homework Statement

George of the Jungle swings on a vine 6.5 meters long. What is the tension in the vine if George whose mass is 75 kg, is moving at 2.4 m/s when the vine is vertical?

Homework Equations

F_tension=F_gravity
F_gravity=mg
F_gravity=Gm₁m₂/d²

The Attempt at a Solution

??

 

[Redbelly98]

F_tension=F_gravity
F_gravity=mg

Why do you think that F_tension = F_gravity ?