I have the question:

Here is my attempt is this correct ?

(I would put this question on physics SE however every question I have put up so far is apparently "not related to physics" and is a "homework question")
I have the question:

Here is my attempt is this correct ?

(I would put this question on physics SE however every question I have put up so far is apparently "not related to physics" and is a "homework question")
Key concepts:
At rest: $$\sum F = T - mg = 0 \\ T = mg$$
Going up: $$\sum F = T - mg = ma \\ T = m(a+g) = m\left(\frac{v_f-v_i}{t}+g\right)$$
Going down: $$\sum F = mg - T = ma \\ T = m(g-a) = m\left(g-\frac{v_f-v_i}{t}\right)$$