How do I use Newtons second law of motion to find tension on a rope?

The rope is holding a gymnast that has a mass of 48.5 Kg, am i correct in calculating her weight as W= M(48.5) * a (9.81 - the force of gravity) = 475.8N?

2 answers

correct.
F = m dV/dt = m a (if m is constant)
Nothing is accelerating here if the gymnast is not moving
so
Force up by the rope - force of gravity down = m * 0
T = tension = force up by rope
T - m g = 0
T = m g
T = 48.5 * 9.81 Newtons