The speed of sound in air is \( 340 \mathrm{~ms}^{-2} \). A loudspeaker placed between two walls A and \( \mathrm{B}, \mathrm{br} \) nearer to wall A than B , is sending out constant sound pulses. How far is the speaker from wall B if it is 200 m from wall A and the time between the two echoes received is 0,176 seconds?

\( \left. \begin{array} { c } { L = L _ { 0 } \sqrt { 1 - \frac { v ^ { 2 } } { c ^ { 2 } } } } \\ { = 90 \sqrt { 1 - \frac { ( 0.8 C ) ^ { 2 } } { ( 3 \times 10 ^ { 8 } ) ^ { 2 } } } = 54 m } \end{array} \right. \)

\( b= \) Expresar 40 kgf en N

Per stimare lo spessore di una moneta da 10 centesimi di misura con un righello l'altezza della pila di monete ot- tenuta. La misura e e \( (2,9 \pm 0,1) \mathrm{cm} \), dove \( 0,1 \mathrm{~cm} \) è la sen- sibilità del righello. - Stima lo spessore della moneta. \( \quad[(1,93 \pm 0,07) \mathrm{mm}] \)

Arus listrik sebesar 5 mA mengalir pada suatu kawat penghantar selama 0,1 sekon. Berapa besar muatannya ?

In one of the processes on the production line at a Sugar Mill, a quantity of gas occupying an original volume of \( 1500 \mathrm{dm}^{3} \) and at an original temperature of \( 300^{\circ} \mathrm{C} \) is expanded adiabatically to a temperature and pressure of \( 135^{\circ} \mathrm{C} \) and 200 kPa respectively. After this adiabatic expansion the gas is heated at constant volume until a pressure of 300 kPa is reached. Given: \( \mathrm{R}=0.286 \mathrm{~kJ} \cdot \mathrm{~kg}^{-1} \cdot \mathrm{~K}^{-1} ; \quad \mathrm{C}_{\mathrm{p}}=1.001 \mathrm{~kJ} \cdot \mathrm{~kg}^{-1} \cdot \mathrm{~K}^{-1}, 1 \mathrm{dm}=10^{-1} \mathrm{~m} \) Assist the production supervisor to: 1.1 Draw a fully labelled \( \mathrm{P}-\mathrm{V} \) diagram for this multi-process system. 1.2 Find the mass of the gas and pressure of the gas before the adiabatic expansion process. 1.3 Find the final volume and final temperature after both processes. 1.4 Find the specific work and specific heat transferred after both processes.