$A$ uniform rod of length $1\, m$ and mass $4\, kg$ is supported on two knife-edges placed $10\, cm$ from each end. $A$ $60\, N$ weight is suspended at $30\, cm$ from one end. The reactions at the knife edges are:

In a physical balance working on the principle of moments,when $5\, mg$ weight is placed on the left pan,the beam becomes horizontal. Both the empty pans of the balance are of equal mass. Which of the following statements is correct?

$A$ physical balance has its arms of unequal length. $A$ body weighs $18 \,kg$ if kept in one pan and weighs $8 \,kg$ if kept in the other pan. The true weight of the body is ............. $kg$

$A$ uniform meter scale is balanced at the $30 \ cm$ mark on a knife edge,when weights of $60 \ N$ and $10 \ N$ are suspended at the $10 \ cm$ and $80 \ cm$ marks,respectively. The mass of the meter scale is: $(g = 10 \ m/s^2)$ (in $kg$)

$A$ uniform rod $AB$ of length $\ell$ and mass $M$ is suspended from a point at a variable distance $x$ from end $A$,as shown. To keep the rod horizontal,a mass $m$ is suspended from its end $A$. $A$ set of $(m, x)$ values is recorded. The appropriate variables that give a straight line when plotted are:

$A$ uniform rod of mass $250 \ g$ having length $100 \ cm$ is balanced on a sharp edge at $40 \ cm$ mark. $A$ mass of $400 \ g$ is suspended at $10 \ cm$ mark. To maintain the balance of the rod,the mass to be suspended at $90 \ cm$ mark is: (in $g$)