Question

Two blocks of masses $10kg$ and $20kg$ are connected by a massless string and are placed on a smooth horizontal surface as shown in the figure. If a force $F=600$ $N$ is applied to $10kg$ block, if a force $F$ is applied to $20kg$ block, then the tension in the string is

• A. $100N$
• B. $200N$
• C. $300N$
• D. $400N$

Answer 1

Answer: (D)

Here, $m_{(}1)=10kg,m=20kg,F=600N$
Let T be tension of the string and a be common acceleration of the system.
$a=\frac{F}{m_1+m_2}=\frac{600N}{10kg+20kg}=\frac{600}{30}m{s}^{-2}=20m{s}^{-2}$
When force F is applied on $10kg$ block, then the tension in the string is $T_2=m_{2}a=(20kg)(20m{s}^{-2})=400N$