Question

a block of mass 20 kg hangs from a ceiling by a cord. calculate the tension in the cord

Answer 1

Let's apply the Newton's Second Law of Motion:

$$\sum F_y=ma_y=0,$$ $$T-mg=0,$$ $$T=mg=20\ kg\cdot 9.8\dfrac{m}{s^2}=196\ N.$$

Answer:

$T=196\ N.$