Question

In a figure a block of mass 10 kg is in equilibrium. Identify the string in which the tension is zero.

• A. B
• B. C
• C. A
• D. None of the above

Answer 1

Answer: (D)

None of the above

The system is in equilibrium

$T_a$ , tension in the spring $A$ is $mg=100N$

We can apply Lammy's theorem for this system

$T_a/sin(90+30)=T_b/sin\left(90\right)=T_c/sin\left(150\right)$

From here we can see that tension is not zero in any of the rope.