For the given figure,if the block remains in equilibrium,find the frictional force between the block and the wall in $N$.

Which bond angle $\theta$ gives maximum dipole moment for a triatomic molecule $XY_2$?

Excretory organs in $Taenia$ are

$A$ particle executes simple harmonic motion between $x = -A$ and $x = +A$. It starts from $x = 0$ and moves in the $+x$ direction. The time taken for it to move from $x = 0$ to $x = \frac{A}{2}$ is $T_1$,and the time taken to move from $x = \frac{A}{2}$ to $x = \frac{A}{\sqrt{2}}$ is $T_2$. Then:

In how many ways can $7$ men and $7$ women be seated around a round table such that no two women sit together?

If $p \rightarrow (q \vee r)$ is false,then the truth values of $p, q, r$ are respectively