Question

An electric lamp of mass 900g hangs on a flex, which is pulled aside by a horizontal string until the flex makes an angel of 30° by with the vertical. Find the tension in the string and in the flex?

Answer 1

The tension in the flex:

$$T_1=\frac{mg}{\cos{30}}=\frac{(0.9)(9.8)}{\cos{30}}=10.2\ N$$

The tension in the string

$$T_2=mg\tan{30}=(0.9)(9.8)\tan{30}=5.1\ N$$