What is a disadvantage of using biomass as an energy resource?

A 50.0 Watt stereo emits sound waves isotropically at a wavelength of 0.700 meters. This stereo is stationary, but a person in a

photoshop1234 [79]

Answer:

a) f' = 432 Hz

b) I = 8.12*10^-4 W/m^2

Explanation:

a) To calculate the frequency of sound waves that car receives, you take into account the Doppler effect. In this case (observer moves away of the source) you have the following formula:

$f'=f(\frac{v-v_o}{v+v_s})$ (1)

where

f: frequency of the source = ?

v: speed of sound = 343 m/s

vo: speed of the observer = 40.0 m/s

vs: speed of the source = 0 m/s (stationary)

You replace the values of all parameters in the equation (1):

To calculate f' you first calculate the frequency of the sound wave, by using the following formula:

$v=\lambda f\\\\$

v: speed of sound

λ: wavelength = 0.700 m

$f=\frac{v}{\lambda}=\frac{343m/s}{0.700m}=480Hz$

Next, you replace the values of all parameters in the equation (1):

$f'=(490Hz)(\frac{343m/s-40.0m/s}{343m/s})=432Hz$

hence, the frequency perceived by the car is 432 Hz

b) To calculate the power of the sound wave, when the car is 70.0 maway from the speaker, you use the following formula:

$I=\frac{P}{4\pi r^2}$

P: power of the source = 50.0 W

r: distance to the source = 70.0 m

$I=\frac{50.0 W}{4\pi(70.0m)^2}=8.12*10^{-4}\frac{W}{m^2}$

hence, the intensity is 8.12*10^⁻4 W/m^2

3 0

3 years ago

I need help plz and thank you this is do

love history [14]

Answer:

Oh I am sorry this is my first time on brainly i dont how to exit and sorry but dont know the answer

Explanation:

4 0

3 years ago

PLZ HELP IM REALLY CONFUSED a boy is playing catch with his friend. He throws the ball straight up. When it leaves his hand, the

erastovalidia [21]

Answer:

K.E = 100 J

Final P.E = 100 J

Explanation:

The kinetic energy of any object can be given by the following formula:

$K.E = (\frac{1}{2})mv^{2}$

where,

K.E = Kinetic Energy

m = mass of ball = 2 kg

v = speed of ball

Initially, v = 10 m/s. Therefore, the initial K.E is given as:

$K.E = (\frac{1}{2})(2\ kg)(10\ m/s)^{2}$

Now, at the highest point the K.E of the ball becomes zero. because the ball stops for a moment at the highest point and its velocity becomes zero. So, from Law of Conservation of energy:

Initial K.E + Initial P.E = Final K.E + Final P.E

Initial P.E is also zero due to zero height initially.

K.E + 0 = 0 + Final P.E

<u>Final P.E = 100 J</u>

3 0

3 years ago

The figure above shows 4forces 3N, 10N, 3√3N, and 6N acting on a particle P. The resultant of the four forces is.

Brilliant_brown [7]

As you gave no pic I took them on one lined

F_1=3N
F_2=10N
F_3=3root 3 N
F_4=6N

$\\ \sf\longmapsto F_{net}=F_1+F_2\dots$

$\\ \sf\longmapsto F_{net}=3+10+6+3\sqrt{3}$

$\\ \sf\longmapsto F_{net}=19+3(1.732)$

$\\ \sf\longmapsto F_{net}=19+5.196$

$\\ \sf\longmapsto F_{net}=24.196N$

6 0

3 years ago

A ray of yellow light (f = 5.09 × 1014hz) travels at a speed of 2.04 × 108meters per second in

denis23 [38]

Velocity = fλ

where f is frequency in Hz, and λ is wavelength in meters.

2.04 * 10⁸ m/s = 5.09 * 10¹⁴ Hz * λ

(2.04 * 10⁸ m/s) / (5.09 * 10¹⁴ Hz ) = λ

4.007*10⁻⁷ m = λ

The wavelength of the yellow light = 4.007*10⁻⁷ m

8 0

3 years ago