(6) first choice: the frequency appears higher and wavelength is shorter.
The car approaches a stationary observer and so the sound will appear to have shorter wavelength. This creates an effect of its siren to sound with higher frequency than it would do if both were stationary.
(7) The Doppler formula for frequency in the case of a stationary observer and source approaching it is as follows:
The wavelength is then
The third choice "0.80m; 431Hz" is correct
Answer:
P = 40.7kPa
Explanation:
To find the pressure on a surface 6 meter below you use the following formula, which takes into account the heights in which pressures are measured and also the density of the fluid and the gravitational acceleration:
(1)
P2: pressure for a height of -6 m = ?
P1: pressure for a height of -2 m = 1.5kPa = 1500 Pa
ρ: density of water = 1000kg/m^3
g: gravitational acceleration = 9.8 ms^2
y2: -6m
y1: -2m
(the height is measure from the water level, because of that, the heights are negative)
You solve the equation (1) for P1:
(2)
Next, you replace the values of all variables in equation (2):
hence, the pressure on a surface 6 m below the water level is 40.7kPa