Answer
$a=0.14m/s^2$
Work Step by Step
The man's upward movement is influenced by 3 forces:
- The tension in the half rope in the man's hands $T_1$ and the tension in the other half tied to his waist $T_2$. Both forces pull the man upward and result from the pulling by his hands, so $T_1=T_2=358N$
- The man's weight $mg$, which points downward
According to Newton's 2nd Law, we have $$\sum F=T_1+T_2-mg = ma$$ $$(2\times358N)-(72kg\times9.8m/s^2)=(72kg)a$$ $$(72kg)a=10.4N$$ $$a=0.14m/s^2$$
