Which one of the following is not included under in-situ conservation?

$A$ gramophone record is revolving with an angular velocity $\omega$. $A$ coin is placed at a distance $R$ from the centre of the record. The static coefficient of friction is $\mu$. The coin will revolve with the record if

$A$ nucleus of an element $_{84}X^{202}$ emits an $\alpha$-particle first,a $\beta$-particle next,and then a gamma photon. The final nucleus formed has an atomic number:

$\int_{-1}^1 \frac{\cosh x}{1+e^{2 x}} d x$ is equal to :

The equation of the parabola with focus $(0,0)$ and directrix $x+y=4$ is

If $\sqrt{\frac{y}{x}}+\sqrt{\frac{x}{y}}=2$,then $\frac{d y}{d x}$ is equal to