$A$ body $A$ starts from rest with an acceleration $a_1$. After $2 \ s$,another body $B$ starts from rest with an acceleration $a_2$. If they travel equal distance in the $5^{th} \ s$ after the start of $A$,then the ratio $a_1 : a_2$ is equal to

Haploids are more suitable for mutation studies than diploids. This is because

At higher altitude,the boiling point of water is $95\,^{\circ}C$. The amount of $NaCl$ added to $1\, kg$ of water $(K_b = 0.52\, K\, kg\, mol^{-1})$ in order to raise the boiling point of the solution to $100\,^{\circ}C$ (assuming $90\%$ ionization of $NaCl$) is ........... $g$.

$A$ mass of $0.5\, kg$ moving with a speed of $1.5\, m/s$ on a horizontal smooth surface,collides with a nearly weightless spring of force constant $k=50\, N/m$. The maximum compression of the spring would be ................. $m$.

$A$ radioactive nucleus undergoes a series of decays according to the scheme:
$A \xrightarrow{\alpha} A_1 \xrightarrow{\beta} A_2 \xrightarrow{\alpha} A_3 \xrightarrow{\gamma} A_4$
If the mass number and atomic number of $A$ are $180$ and $72$ respectively,what are these numbers for $A_4$?

$\int \frac{dx}{1-\cos x-\sin x}$ is equal to