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 force $F=600N$ is applied to $20kg$ block, then the tension in the string is

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

Answer 1

Answer: (B)

200 N

Given

Mass of body $\left(m_2\right)=10kg$

Mass of body $\left(m_1\right)=20kg$

Force applied $=600N$

Let a is the acceleration of the system.

When force $F$ applied on $A$,

using free body diagram

For body $m_1$,

$F-T=m_{1}a$ ............(1)

for body m2,

$T=m_{2}a$ ................(2)

solving equation (1) and (2),

$a=\frac{F}{(m_1+m_2)}$

$a=\frac{600}{(10+20)}$

$a=20m/s^2$

Now, $600-T=20\ast 20$........................(Using eqn. (1))

$T=200N$