Calculate the ratio of intensity of wave train $A$ to wave train $B$

In the given figure the string has mass $4.5 \mathrm{g}$. If the time taken by a transverse pulse produced at the floor to reach the pulley is $10\mathrm{p}$ ms then $\mathrm{p}$ is : $\left(g=10{ \mathrm{m} \mathrm{s}}^{-2}\right)$.

A string vibrate according to the equation $y=5\sin \left(\frac{\pi x}{3}\right)\cos \left(40\pi t\right)$ where $x$ and $y$ are in $\mathrm{cm}\text{'}s$ and $t$ is in second.

The figure shows a snap photograph of a vibrating string at $t=0$. The particle $P$ is observed moving up with velocity $20\sqrt{3} \mathrm{cm} {\mathrm{s}}^{-1}$. The tangent at $P$ makes an angle $60°$ with $\mathrm{x}$ -axis (i) Find the direction in which the wave is moving (ii) the equation of the wave (iii) the total energy carried by the wave per cycle of the string. [Assuming that $\mu$, the mass per unit length of the string $=50 \mathrm{g} {\mathrm{m}}^{-1}]$

The displacement of the medium in a sound wave is given by the equation $y_1=A\cos \left(ax+bt\right)$ where $A$, $a$and $b$ are positive constants. The wave is reflected by an obstacle situated a $x=0$. The intensity of the reflected wave is $0.64$ times that of the incident wave. If

(i) the wavelength and frequency of incident wave are $\frac{P\pi }{a},\frac{b}{Q\pi }$ respectively.
(ii) the equation for the reflected wave is $y_r=-R A\cos \left(ax-bt\right)$
(iii) In the resultant wave formed after reflection, the maximum and minimum values of the particle speeds in the medium are$SAb, TAb$ .

(iv) the resultant wave as a superposition of a standing wave and a travelling wave is$y=-UA\sin ax \sin bt+VA\cos (ax+bt)$.

then find $P+Q+R+S+T+U+V$.