Answer:
The ratio of initial to final speed of sound is given as 1.28.
Explanation:
As per the thermodynamic relation of isentropic expansion

Here
is the pressure at point 1 which is given as 2.2 MPa
is the temperature at point 1 which is given as 77 °C or 273+77=350K
is the pressure at point 1 which is given as 0.4 MPa
is the temperature at point 2 which is to be calculated- k is the ratio of specific heats given as 1.4
Substituting values in the equation

As speed of sound c is given as

for initial to final values it is given as

As values of k and R is constant so the ratio is given as

Substituting values give

So the ratio of initial to final speed of sound is 1.28.
<u>Answer:</u>
Things become hot and cold because of the transfer of energy.
<u>Explanation:</u>
The energy possessed by an object or system is called thermal energy and heat is the flow of this energy. While the law of conversation of energy states that energy is not destroyed or created, it just transfers from one object to another.
When a hot object is placed in normal conditions, it transfers heat to the environment until both are at the same temperature and heat transfers from the environment to the cold objects placed in normal conditions.
I believe the answer would be mass. Low mass stars and medium mass stars often become white dwarfs when they die while high mass stars explode in violent explosions called supernovas and usually leave behind a black hole or a neutron star.