Question on Heat, Pressure, and Doppler's Effect

In summary, the first conversation involves adding 85g of ice to 310g of water at 24°C and finding the final temperature after the ice melts and reaches equilibrium. The second conversation involves finding the height of the atmosphere using the density of air and air pressure at Earth's surface. The third conversation involves using the Doppler shift formula to find the speed of a car using the reflected signal from a radar gun. The resulting answer of 876,355 mph may be incorrect.
  • #1
Neckrow
1
0

Homework Statement


I have 310g mass 24°C Water and I add 85g of 0°C ice.

What is the final temperature after the ice melted and come to equilibrium?

Homework Equations


I think its Q=mcΔt
with a mix of Q=mL

The Attempt at a Solution


I have no idea.

Homework Statement


I have density of air of 1.2 kg/m³. Air pressure at Earth surface 1.01x10^5 Pa. I need to find the height of the atmosphere.

Homework Equations


P=pgh

The Attempt at a Solution


So I made the problem; 1.01x10^5=(1.2kg/m³)(9.8m/s)(height) and found for height and got 8588.435m. Is that right? I don't know what a "believable" answer would look like.

Homework Statement


This is suppose to be a scenario where the police is using a radar to find the speed of passing cars. So, the velocity is in EM (speed of light). There is a note that says there are two Doppler shifts so I use a squared version of the formula. The Radar is bounced off the moving cars and the Doppler-shifted frequency of the echo's signal is compared to the frequency of the original signal.

The microwave frequency of 1.4x10^9 Hz is used for the original signal and the reflected signal is 350 Hz lower than that. (the car is moving away from the radar gun). What is the speed of the car in mph?

Hint: there are two Doppler shifts

Homework Equations


freflected = (Vw/(Vw+Vcar))² f original

The Attempt at a Solution



(1.4x10^9)-350 Hz = (3x10^8/(3x10^8+X)²(1.4x10^9)

There is something I'm missing but I dunno. I solve the f[/I]reflected and divide by f original. I then square root both sides and divide Vw by freflected and solve for X
 
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  • #2
. X= (3x10^8*sqrt(1.4x10^9/350)-3x10^8)This gives me an answer of 876,355 mph which does not seem right.
 

Related to Question on Heat, Pressure, and Doppler's Effect

1. What is heat and how is it measured?

Heat is a form of energy that is transferred between objects or systems due to a temperature difference. It is typically measured in units of joules (J) or calories (cal). One common method of measuring heat is using a thermometer, which measures the average kinetic energy of the molecules in a substance.

2. How does pressure affect the behavior of gases?

Pressure is the force exerted per unit area on a surface. In gases, an increase in pressure leads to a decrease in volume, while a decrease in pressure leads to an increase in volume. This is known as Boyle's Law. Additionally, an increase in pressure can also increase the temperature of a gas, known as the Joule-Thomson effect.

3. What is the Doppler's Effect and how does it relate to sound?

The Doppler's Effect is the change in frequency or wavelength of a wave as perceived by an observer moving relative to the source of the wave. This phenomenon can be observed in sound waves, where an approaching sound source will have a higher frequency and a receding source will have a lower frequency. This is commonly experienced with the sound of a passing ambulance or train.

4. How does temperature affect the speed of sound?

The speed of sound is directly proportional to the temperature of the medium it is traveling through. This means that as the temperature increases, the speed of sound also increases. This is because higher temperatures lead to an increase in the average kinetic energy of the molecules in the medium, allowing sound waves to travel faster.

5. How do heat and pressure play a role in weather patterns?

Heat and pressure are both important factors in determining weather patterns. The uneven heating of the Earth's surface by the sun creates differences in air pressure, which leads to the movement of air masses and the formation of weather systems. Additionally, changes in temperature and pressure can also cause changes in wind patterns, precipitation, and other weather phenomena.

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