If a body is projected with an angle $\theta$ to the horizontal,then

If the circle $x^2+y^2+6x-2y+k=0$ bisects the circumference of the circle $x^2+y^2+2x-6y-15=0$,then $k$ is equal to

The horizontal and vertical displacements of a projectile at time $t$ are $x=36 t$ and $y=48 t-4.9 t^2$,respectively. Initial velocity of the projectile in $m/s$ is

In the reaction of $BaO_2$ with dilute $H_2SO_4$,what are the oxidation states of the most electronegative element in the products?

Let $PS$ be the median of the triangle with vertices $P(2, 2)$,$Q(6, -1)$,and $R(7, 3)$. The equation of the line passing through $(1, -1)$ and parallel to $PS$ is:

$A$ cylindrical rod with one end in a steam chamber and the other end in ice results in the melting of $0.1 \, g$ of ice per second. If the rod is replaced by another with half the length and double the radius of the first,and if the thermal conductivity of the material of the second rod is $1/4$ that of the first,the rate at which ice melts in $g/s$ will be: