- (A) is incorrect. Weight is the force exerted by gravity on an object, not the amount of matter.
- (B) is incorrect. Mass is the amount of matter, not the force due to gravity.
- (C) is correct. Volume is indeed the amount of space occupied by a substance.
- (D) is correct. Temperatures below \(0^\circ\)C are possible in Celsius scale, but negative temperatures are not possible in the Kelvin scale. - (E) is correct. Precision refers to the closeness of repeated measurements. Thus, the correct answer is (3) (C), (D) and (E) Only.
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\(^{-2}\).
