Question

Calculate the tension in the string shown in the following figure. The pulley and the string are light and all the surfaces are frictionless. Take g = 10 m/s².

Answer 1

The free-body diagrams for both the bodies are shown below:  

T + ma =mg    ...(i)
and T = ma    ...(ii)

From equations (i) and (ii), we get:
ma + ma = mg
⇒ 2ma = g
\[\Rightarrow a = \frac{g}{2} = \frac{10}{5} = 5 m/ s^2\]
From equation (ii),
T = ma = 5 N