Given below are two statements: one is labelled as Assertion \(A\) and the other as Reason \(R\):
Assertion \(A\): A sound wave has higher speed in solids than in gases.
Reason \(R\): Gases have higher value of Bulk modulus than solids.
Step 1: Evaluate the truth of \(A\) and \(R\). Sound travels faster in solids than in gases due to the higher density and elastic properties of solids, not gases.
Step 2: Determine the correctness of \(R\). In fact, solids generally have a higher Bulk modulus than gases, contradicting the statement of \(R\).
Conclusion: Assertion \(A\) is true, stating that sound waves travel faster in solids is correct, but Reason \(R\) is false as gases typically have a lower Bulk modulus than solids.
A flexible chain of mass $m$ is hanging as shown. Find tension at the lowest point. 

In the given figure, the blocks $A$, $B$ and $C$ weigh $4\,\text{kg}$, $6\,\text{kg}$ and $8\,\text{kg}$ respectively. The coefficient of sliding friction between any two surfaces is $0.5$. The force $\vec{F}$ required to slide the block $C$ with constant speed is ___ N.
(Given: $g = 10\,\text{m s}^{-2}$) 
Two circular discs of radius \(10\) cm each are joined at their centres by a rod, as shown in the figure. The length of the rod is \(30\) cm and its mass is \(600\) g. The mass of each disc is also \(600\) g. If the applied torque between the two discs is \(43\times10^{-7}\) dyne·cm, then the angular acceleration of the system about the given axis \(AB\) is ________ rad s\(^{-2}\).
