When a ceiling fan is switched off,its angular velocity falls to half while it makes $36$ rotations. How many more rotations will it make before coming to rest? (Assume uniform angular retardation)

What do you understand by isoelectronic species? Name a species that will be isoelectronic with each of the following atoms or ions.
$(i)$ $F^{-}$ $(ii)$ $Ar$ $(iii)$ $Mg^{2+}$ $(iv)$ $Rb^{+}$

If $I_n = \int x^n \cdot e^{cx} \, dx$ for $n \geq 1$,then $c \cdot I_n + n \cdot I_{n-1}$ is equal to

If the curves $x^2+p y^2=1$ and $q x^2+y^2=1$ are orthogonal to each other, then

Consider the following statements $A$ and $B$ and identify the correct answer.
$A$. In an elastic collision,if a body suffers a head-on collision with another of the same mass at rest,then the first body comes to rest while the other starts moving with the velocity of the first one.
$B$. Two bodies of equal mass suffering a head-on elastic collision merely exchange their velocities.

The maximum tension a rope can withstand is $60 ~kg-wt$. The ratio of maximum acceleration with which two boys of masses $20 ~kg$ and $30 ~kg$ can climb up the rope at the same time is