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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.
Solution
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
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