How Do You Calculate Tension in a String with Mass and Acceleration?

[rchenkl]

Homework Statement

A string is attached to a mass and a pulley at the top end and the mass is free to move and descends with a constant acceleration, a.
By applying Newton's Laws to mass m, find an expression for the tension in the string, in terms of m, a and the acceleration due to gravity, g.

Homework Equations

F=ma

The Attempt at a Solution

I was thinking the net force downwards is mg-Tension force. And the net force results acceleration. So ma=mg-tension. is that correct?

 

[dx]

That's correct.