What is the $IUPAC$ name of the following compound?

If $(1+x+x^2+x^3)^5 = \sum_{k=0}^{15} a_k x^k$,then $\sum_{k=0}^7 a_{2k}$ is equal to

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

The adsorption isotherm for a gas is given by the relation $x = \frac{ap}{1 + bp}$,where $x$ is moles of gas adsorbed per gram of the adsorbent,$p$ is the pressure of the gas,and $a$ and $b$ are constants. Then $x$:

$A$ launching vehicle carrying an artificial satellite of mass $m$ is set for launch on the surface of the earth of mass $M$ and radius $R$. If the satellite is intended to move in a circular orbit of radius $7R$,the minimum energy required to be spent by the launching vehicle on the satellite is (Gravitational constant $= G$)