A materiel that allows electricity to flow easily is called an

A 2.15-MHz sound wave travels through a pregnant woman’s abdomen and is reflected from the fetal heart wall of her unborn baby.

MrRa [10]

Answer:

v= 0.0316 m/s

Explanation:

We need to use the Doppler Effect defined as the change in frequency of a wave in relation to an observer who is moving relative to the wave source.

Notation

Let v= magnitude of the heart wall speed

V= speed of sound

fh= the frequency the heart receives (and reflects)

fi= original frequency

ff= reflected frequency

fb= frequency for the beats

Apply the Doppler Effect formula

Since the heart is moving observer then the device is a stationary source, and we have this formula

fh = [(V+ v)/(v)] fi (1)

We can consider the heart as moving source and the device as a stationary observer, and we have this formula

ff = [(V)/(V-v)] fh (2)

The frequency for the beats would be the difference from the original and the reflected frequency

fb = ff -fi (3)

Replacing equations (1) and (2) into equation (3) we have:

$f_b = \frac{V}{V-v} \frac{V+v}{V}f_i - f_i$

$f_b = f_i ( \frac{V+v}{V-v} -1)$

fb = fi(V+v -V+v)/(V-v)

$f_b = \frac{2v}{V-v}$

Solving for v we have:

$v = V (\frac{f_b}{2f_o - f_b})$

$v = 1510 m/s (\frac{90 Hz}{2∗2150000Hz - 90 Hz})= 0.0316 m/s$

5 0

4 years ago

Two circuits, one series and one parallel, use light bulbs to provide resistance. Both circuits have the same number of light bu

SashulF [63]

Answer: B.

but the resistance is lower in the parallel circuit.

Explanation:

A circuit with parallel connections has a lower total resistance than the resistors connected in series. This is consistent with conservation of charge. The power dissipated by each resistor is considerably higher in parallel than when connected in series to the same voltage source.

4 0

4 years ago

How does blue light differ from red light?

mixas84 [53]

Due to the difference ofwavelength, blue has short wavelenght compared with red(red has long wavelength)

3 0

3 years ago

Suppose you have an accounting background and you are considered an expert in the field of discovering errors in electronic spre

leonid [27]

Answer: True

Explanation: A knowledge engineer is a professional who works to improve and builds with the aid of science and also implements advanced logic and AI( artificial intelligence) in computer systems in order to investigate particular issues.

A knowledge engineer also helps tries to emulate the judgements of man.

Since you are part of the team involved in discovering errors in the electronic spread sheet you are a knowledge engineer.

6 0

3 years ago

"if the left-hand mass is 2.3 kg ,what should the right-hand mass be so that it accelerates downslope at 0.64 m/s2?"

VARVARA [1.3K]

m₁ = 2.3 kg 
θ₁ = 70° 
θ₂ = 17° 
g = 9.8 m/s²

->The component of the gravitational force on m₁ that is parallel down the incline is: 
F₁ = m₁ × g × sin(θ₁) 
F₁ = (2.3 kg) × (9.8 m/s²) × sin(70°) = 21.18 N 

->The component of the gravitational force on m₂ that is parallel down the incline is: 
F₂ = m₂ × g × sin(θ₂) 
F₂ = m₂ × (9.8 m/s²) × sin(70°) = m₂ × (2.86 m/s²) 

Then the total mass of the system is:
m = m₁ + m₂ 
m = (2.3 kg) + m₂ 

If it is given that m₂ slides down the incline, then F₂ must be bigger than F₁, 
and so the net force on the system must be:
F = m₂×(2.86 m/s²) - (21.18 N) 

Using Newton's second law, we know that
F = m × a
So if we want the acceleration to be 0.64 m/s², then
m₂×(2.86 m/s²) - (21.18 N) = [(2.3 kg) + m₂] × (0.64 m/s²) 
m₂×(2.86 m/s²) - (21.18 N) = (1.47 N) + m₂×(0.64 m/s²) 
m₂×(2.22 m/s²) = (22.65 N) 
m₂ = 10.2 kg

5 0

4 years ago