5. A sound wave travels at 345 m/s with a wavelength of 15 cm. (a) What is the

a ultrasonic wave at 8x10^4 Hz is emitted into a vien where the speed of sound in blood is 1570 m/s. the wave reflects off the r

Aneli [31]

Answer: 0.392 m/s

Explanation:

The Doppler shift equation is:

$f'=\frac{V+V_{o}}{V-V_{s}} f$

Where:

$f=8(10)^{4} Hz$ is the actual frequency of the sound wave

$f'=8.002(10)^{4} Hz$ is the "observed" frequency

$V=1570 m/s$ is the speed of sound

$V_{o}=0 m/s$ is the velocity of the observer, which is stationary

$V_{s}$ is the velocity of the source, which are the red blood cells

Isolating $V_{s}$ :

$V_{s}=\frac{V(f'-f)}{f'}$

$V_{s}=\frac{1570 m/s(8.002(10)^{4} Hz-8(10)^{4} Hz)}{8.002(10)^{4} Hz}$

Finally:

$V_{s}=0.392 m/s$

3 0

3 years ago

What is the difference between an induced and a permanent magnet?

MissTica

INDUCTION MOTOR:-

Speed:-Less speed range than PMAC motors • Speed range is a function of the drive being used — to 1,000:1 with an encoder, 120:1 under field-oriented control

Reliability:-Waste heat is capable of degrading insulation essential to motor operation • Years of service common with proper operation

Power density:-Induction produced by squirrel cage rotor inherently limits power density

Accuracy:-Flux vector and field-oriented control allows for some of accuracy of servos

Cost:-Relatively modest initial cost; higher operating costs

PERMANENT MAGNET MORTOR:-

speed:-VFD-driven PMAC motors can be used in nearly all induction-motor and some servo applications • Typical servomotor application speed — to 10,000 rpm — is out of PMAC motor range

Reliability:-Lower operating temperatures reduces wear and tear, maintenance • Extends bearing and insulation life • Robust construction for years of trouble-free operation in harsh environments.

power density:-Rare-earth permanent magnets produce more flux (and resultant torque) for their physical size than induction types.

Accuracy:-Without feedback, can be difficult to locate and position to the pinpoint accuracy of servomotors

<span>Cost:-Exhibit higher efficiency, so their energy use is smaller and full return on their initial purchase cost is realized more quickly</span>

8 0

3 years ago

Usually, large amount of curent flows in a<br> Circuit due to two reasons ———— and ————.

omeli [17]

Answer:

Explanation:

Possible causes for overcurrent include short circuits, excessive load, incorrect design, an arc fault, or a ground fault. Fuses, circuit breakers, and current limiters are commonly used overcurrent protection (OCP) mechanisms to control the risks

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8 0

3 years ago

Before we understood that objects have a tendency to maintain their velocity in a straight line unless acted upon by a net force

Sveta_85 [38]

Answer:Friction force

Explanation:

The frictional force is responsible for stopping the moving object.

The friction force is provided by nature in the form of air resistance, fluid resistance, Surface resistance.

For surface resistance, the friction force is of two types namely kinetic friction force and static friction force.

Static friction acts when the object is stationary and a force is applied to cause the motion while kinetic friction acts when the body starts moving.

kinetic friction is lesser is in magnitude as compared to static friction.

7 0

3 years ago

the flame on a gas stove heats the bottom of a metal pot. (A) conduction (B)convection (C)radiation. the cold water in a metal p

Sedbober [7]

The flame on a gas stove heats the bottom of a metal pot is conduction.
The sun gives you a sunburn is a radiation

3 0

3 years ago

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