$A$ meter stick is balanced on a knife edge at its centre. When a $10 \ g$ coin is placed on top of the stick at the $12 \ cm$ mark,the stick is found to be balanced at the $45 \ cm$ mark. Then the mass of the meter stick is $.... \ g$.

$A$ hollow tilted cylindrical vessel of negligible mass rests on a horizontal plane as shown. The diameter of the base is $a$ and the side of the cylinder makes an angle $\theta$ with the horizontal. Water is then slowly poured into the cylinder. The cylinder topples over when the water reaches a certain height $h$,given by

If a street light of mass $M$ is suspended from the end of a uniform rod of length $L$ in different possible patterns as shown in the figure,then

$A$ $3\; m$ long ladder weighing $20\; kg$ leans on a frictionless wall. Its feet rest on the floor $1\; m$ from the wall as shown in the figure. Find the reaction forces of the wall and the floor.

An $L$-shaped object,made of two thin rods of uniform mass density and equal length $a$,is suspended from a string as shown in the figure. If $AB = BC = a$,and the angle made by $AB$ with the downward vertical is $\theta$,then:

$A$ metal rod of weight $W$ is supported by two parallel knife-edges $A$ and $B$. The rod is in equilibrium in a horizontal position. The distance between the two knife-edges is $r$. The centre of mass of the rod is at a distance $x$ from $A$. The normal reaction on $A$ is