What is the hybridization state of the central atom in the conjugate base of $NH_4^{+}$ ion?

If $PM$ is the perpendicular from $P(2, 3)$ onto the line $x+y=3$,then the coordinates of $M$ are

$A$ rocket with a lift-off mass $2 \times 10^4 \ kg$ is blasted upwards with an initial acceleration of $5 \ m \ s^{-2}$. The initial thrust of the blast is (Take $g = 10 \ m \ s^{-2}$)

Find the equation of the parabola whose axis is parallel to the $y$-axis and which passes through the points $(0, 4), (1, 9),$ and $(4, 5)$.

The electric field at a place is given by $\overrightarrow E = E_0 \widehat i \, V/m$. $A$ particle of charge $+q_0$ moves from point $A(0, a)$ to $B(a, 0)$ along a circular path. Find the work done by the electric field in this motion.

The number of points in $(-\infty, \infty)$,for which $x^2-x \sin x-\cos x=0$,is