Answer:
ΔT = 4.058 10²⁰ [tex]\frac{S_o^2}{r^2 \ c_e}[/tex]
Explanation:
In this experiment the system can be approximated as a tube with one end open and the other closed.
The open end is where the ultrasound emitter is and the closed end where the limit between the tissue and the bone is, the length of the tube is L = 0.55 cm = 5.5 10⁻³ m
a node is formed at the closed end and a belly at the open end, so the resonance has the form
λ = 4L 1st harmonic
λ = 4/3 L third harmonic
λ = 4/5 L fifth harmonic
λ = 4L / (2n + 1) n = 0, 1, 2, (2n + 1)
This wave is a standing wave therefore energy density remains in place
P = 1/2 ρ v (w S₀)²
angular velocity is related to frequency
w = 2π f
we substitute
E = P = 2π² ρ v f² S₀²
if this energy per unit area is transformed into heat
E = m c_e DT
let's use the concept of density
ρ = m / V
m = ρ V
if there are no losses in the system
½ π² ρ v f² S₀² = ρ V c_e ΔT
ΔT = [tex]\frac{\pi ^2 \ v \f^2 S_o^2}{2V \ c_e}[/tex]
When analyzing this expression the temperature increase is
* quadratic at the frequency and maximum amplitude of the wave
* proportional to the speed of the wave in the tissue
* inversely proportional to tissue volume
we can approximate the volume of the tissue to the volume of a cylinder tube
V = π r² L
ΔT = [tex]\frac{\pi \ v \ f^2 S_o^2 }{r^2 \ L \ c_e}[/tex]
we calculate
ΔT = π 1450 (0.7 10⁶)² S₀² /( r² 5.5 10-3 c_e)
ΔT = 4.058 10²⁰ [tex]\frac{S_o^2}{r^2 \ c_e}[/tex]
You have 3 resistors and a battery to form a closed circuit. Two 2-Ohm resistors are in series with each other. The combination of those two resistors is in parallel with a 4-Ohm resistor. The total voltage of this circuit is 12 Volts. The total current and resistance of this circuit is a. 2 Ohms, 6 Amps b. 8 Ohms, 1.5 Amps c. 6 Ohms, 2 Amps d. 1.5 Ohms, 8 Amps
Answer:
Option 2
Explanation:
Given
Two 2-Ohm resistors are in series and these two resistors are in parallel with a 4-Ohm resistor
Equivalent resistance of two resistors in series = R1 + R2 = 2+2 = 4 Ohm
Equivalent resistance of two 4 Ohm resistors is parallel =1/ (1/4 +1/4) = 2 Ohm
Voltage = 12 Volts.
Hence, current = V/R = 12/2 = 6 Amp
Option 2 is correct
A self-driving car traveling along a straight section of road starts from rest, accelerating at 2.00 m/s2 until it reaches a speed of 25.0 m/s. Then the vehicle travels for 39.0 s at constant speed until the brakes are applied, stopping the vehicle in a uniform manner in an additional 5.00 s.
(a) How long is the self-driving car in motion (in s)?
(b) What is the average velocity of the self-driving car for the motion described? (Enter the magnitude in m/s.) m/s
Answer:
[tex]56.5\ \text{s}[/tex]
[tex]21.13\ \text{m/s}[/tex]
Explanation:
v = Final velocity
u = Initial velocity
a = Acceleration
t = Time
s = Displacement
Here the kinematic equations of motion are used
[tex]v=u+at\\\Rightarrow t=\dfrac{v-u}{a}\\\Rightarrow t=\dfrac{25-0}{2}\\\Rightarrow t=12.5\ \text{s}[/tex]
Time the car is at constant velocity is 39 s
Time the car is decelerating is 5 s
Total time the car is in motion is [tex]12.5+39+5=56.5\ \text{s}[/tex]
Distance traveled
[tex]v^2-u^2=2as\\\Rightarrow s=\dfrac{v^2-u^2}{2a}\\\Rightarrow s=\dfrac{25^2-0}{2\times 2}\\\Rightarrow s=156.25\ \text{m}[/tex]
[tex]s=vt\\\Rightarrow s=25\times 39\\\Rightarrow s=975\ \text{m}[/tex]
[tex]v=u+at\\\Rightarrow a=\dfrac{v-u}{t}\\\Rightarrow a=\dfrac{0-25}{5}\\\Rightarrow a=-5\ \text{m/s}^2[/tex]
[tex]s=\dfrac{v^2-u^2}{2a}\\\Rightarrow s=\dfrac{0-25^2}{2\times -5}\\\Rightarrow s=62.5\ \text{m}[/tex]
The total displacement of the car is [tex]156.25+975+62.5=1193.75\ \text{m}[/tex]
Average velocity is given by
[tex]\dfrac{\text{Total displacement}}{\text{Total time}}=\dfrac{1193.75}{56.5}=21.13\ \text{m/s}[/tex]
The average velocity of the car is [tex]21.13\ \text{m/s}[/tex].
Which statement did John Dalton make about atoms?
A. there are distinct kinds of atoms
B. the atom is made up of smaller particles
C. the atom has a small, dense center
D. the energy of an electron depends on its specific orbit
Answer:
B
Explanation:
Atoms are made by electrons, neutrons and protons
Answer:
A. there are distinct kinds of atoms
Explanation:
According to Dalton's atomic theory, the atom is indivisible. Thus, we know that B is incorrect. Additionally, C can't be correct because when Dalton was alive, the nucleus (the small, dense center) hadn't yet been discovered. Finally, D can't be correct either since Bohr's discoveries about electron orbits hadn't yet been made. Knowing that, it must be A!
Also, I just did the quiz, and it was A. Dalton believed that there are distinct kinds of atoms!
if a car travels 200 m to the east in 8.0s what is the car's average velocity.
Answer:
25mph
Explanation:
you do distance divided by time. 200/8=25
What is the length of a string with a mass of 2.5 kg, with a
tension of 20 N, if the speed of wave on the string is 2 m/s?
a 0.8 m
b 0.4 m
C 0.5 m
d 1.0 m
e 0.1 m
Complete the sentence below using the words provided in parentheses (). For two universes that are the same size, the universe with the faster expansion rate must be _______ (younger/older) than the universe with the slower expansion rate. The slope of the line in the Hubble plot of the ______ (younger/older) universe will be ______ (steeper/flatter)
Answer:
For two universe that is the same size, the universe with the faster expansion rate must be younger than the universe with a slower expansion rate. The slope in the line of the Hubble plot of the older universe will be flatter.
Explanation:
Hubble's law establishes a direct relationship between a galaxy's distance and its redshift-determined recessional velocity. The redshifts of galaxy clusters and distant galaxies are equivalent and proportional to their distances from us, according to Hubble's theorem.
Thus, to copy and complete the given question.
For two universe that is the same size, the universe with the faster expansion rate must be younger than the universe with a slower expansion rate. The slope in the line of the Hubble plot of the older universe will be flatter.
a car traveling in a highway brakes to a stop without skidding. what happens to its kinetic energy? can that energy be recovered and reused?
Answer:
A car traveling on a highway takes to stop without skidding. What happens to its kinetic energy? ... The energy goes to parts of the brakes. No, the energy can only be reused if there is a heat pump present
If a magnet can cut into a small piece , each piece will remain a magnet ? Explain this phenomenon
yes ,each piece will remain a magnet because the small pieces will cut into north and south
Polarizing windows, filters, etc. are often used to reduce the amount of light that enters the lens of a camera or into a room or a car. A library atrium has an overhead skylight that lets in too much light during the day which heats up the interior of the library far too much. The building engineer installs new double paned polarizing sky lights to reduce the intensity. If sunlight, which is unpolarized, has an average intensity of 1366 W/m2 what angle should the polarizing axis of the second pane of the window make with the polarizing axis of the first pane of the window in order to reduce the intensity of the sunlight to 33% of the original value
Answer:
θ = 35.7º
Explanation:
For this exercise we must use the law of Malus
I = I₀ cos² θ
where the angle is between the two polarizers.
When the unpolarized light from the sun reaches the first polarizer, only the light polarized in the direction manages to be transmitted, which is why
I₁ = I₀ /2
this light reaches the second polarizer
I₂ = I₁ cos² θ
I₂ = I₀/2 cos² θ
cos² θ = 2 I₂ / Io
indicate that the transmitted light is 33% = 0.33 I₀
cos² θ = 2 0.33
cos θ = √0.66
θ = cos⁻¹ 0.8124
θ = 35.7º
A uniform rod of length 50cm and mass 0.2kg is placed on a fulcrum at a distance of 40cm from the left end of the rod. At what distance from the left end of the rod should a 0.6kg mass be hung to balance the rod?
a.48 cm
b. 50 cm
c. 45 cm
d. the rod can not be balanced with this mass. e.42 cm
NO LINKS.
A ____________ galaxy has arms of gas and dust; where as _____________ galaxy is a category of galaxy that does not have a distinctive shape.
Question 1 options:
elliptical, an elliptical
irregular, a barred-spiral
bar, a spiral
spiral, an irregular
Answer:
spiral, an irregular
Explanation:
i took the test :)
A 12 ohm resistor and a 24 ohm resistor are connected in parallel across a 6.0 V battery. The correct statement from the following is a. the current is the same in each resistor. b. the power dissipated is the same in each resistor. c. the larger current is in the larger resistor. d. the voltage difference between the ends of each resistor is the same.
Answer:
d. the voltage difference between the ends of each resistor is the same.
Explanation:
A resistor is a circuit component that offers opposition to the flow of current. Resistors may be connected in series or in parallel.
Resistors in parallel are connected at common junctions. The potential difference (voltage difference between the ends of each resistor) is the same for each resistor in a parallel connection while the current across each resistor is different.
what's the temperature 32°F in degrees Celsius
Answer:
0 degrees Celsius
Explanation:
HELP PLEASEEEEEEEEEEEE
3
Explain the working principles
of 아
has/ Constant volume
thermometer
a gas
Answer:
A constant volume gas thermometer works on a thermometric property of " change in pressure with temperature at a constant volume"
Bent over row trains what specific muscle?
O A. triceps
O B. trapezius
O C. latissimus dorsi
D. pectoralis major
Please help
Which of the following is an example of heat energy being transformed into mechanical energy
A. An electric mixer being used to beat eggs
B. A person turning a crank to sharpen a pencil.
C. A car battery being used to power a car radio
D. Boiling water producing steam used to power a boat
Answer:
D
Explanation:
because it is the only one that has something to do with heat keyword would be boiling
what is the best structure for a egg dropping project you will be name brainiest
Answer:
bubble wrap in stuff animal
Explanation:
did it
Answer:
i would say putting like pillows around it i had to do it once and i won like that so
Explanation:
If the period of a given wave is 6 seconds, what is the frequency of the wave?
A. 17 Hz
B. 0.17 Hz
C. 0.017 Hz
D. 1.7 Hz
Answer:
[tex]\text{B. }0.17\:\mathrm{Hz}[/tex]
Explanation:
The frequency of a wave is given by [tex]f=\frac{1}{t}[/tex], where [tex]t[/tex] is the period of the wave.
Substituting [tex]t=6[/tex], we get:
[tex]f=\frac{1}{6}\approx \boxed{\text{B. }0.17\:\mathrm{Hz}}[/tex]
_PCi5 + _H20 + _H3PO4 _HCI
A.) 1,3,1,5
B.) 2,4,1,5
C.) 1,4,1,5
D.) 2,1,2,5
Answer:
C
Explanation:
because of the kids are doing well and staying in the middle of the day early to get a new phone number for home now deep
The botanist from the nursery is planning to develop a large number of new spider plants with larger flowers. Identify the type of reproduction the botanist should use to develop the new spider plants and explain why this type of reproduction is preferable.
Answer:
Sexual reproduction.
Explanation:
Reproduction can be defined as a biological process which typically involves living organisms producing an offspring.
Basically, there are two (2) methods of reproduction and these are;
I. Asexual reproduction: it involves the cloning of a living organism to produce an offspring because there is only a single parent.
II. Sexual reproduction: it involves the combination of the genome (gamete) of a male and female living organism during fertilization.
In this scenario, the botanist from the nursery plans to develop a large number of new spider plants that has larger flowers. Thus, the type of reproduction the botanist should use to develop the new spider plants is sexual reproduction because it would help the parent plant reproduce offsprings with different traits such as spider plants with large flowers. Also, the botanist should use sexual reproduction rather than asexual reproduction because asexual reproduction will only make the parent plant reproduce that have the same type of traits as themselves.
Which of the following is an example
of a measure of the
mass of an object?
A. 65 centimeters
B. 65 grams
C. 65 light-years
D. 65 feet
Answer:
Grams
Explanation:
Because that is the definition
Answer:
65 grams
Explanation:
What are the parts of a torch light name them
Answer: Batteries,the case of the torch,reflector,contacts,switch and lens and the light/bulb Hope i helped :)
when a light beam emerges from water into air, the average light speed ____.
a. increases
b. decreases
c. remains the same
d. not provided
Answer:
Increases
Explanation:
The light is emerging from a denser medium to rarer medium so the average light speed increases.
When a light beam emerges from water into air, the average light speed increases.
What is refraction?The bending of a ray passes at an angle from one medium to another in which the speed will be different, as when light passes from air into water and also from water into air can be known as refraction.
When light travels from water to air, the angle from water to air the light gets speeds up and then its changes direction. The light turns away from the normal line. Because the light moves from a denser medium to the rarer medium. But from air to water the speed will be decreased because in that case the light travels from the rarer medium to the denser medium.
Hence, the light beam when passes, the average speed gets increased.
So, Option A is the correct answer.
Learn more about refraction,
https://brainly.com/question/2660868
#SPJ2
plz help.me guys
6xy – 12x y + 15x3y? – 3x?y? by 3x²y
Answer:
2xy-12xy+15x3y?-3x?y?by3l 3x2y
Which organisms were first responsible for depleting carbon dioxide from the atmosphere, replacing it with oxygen?
A) Plants
B) Dinosaurs
C) Cyanobacteria
D) Trilobites
During a football game player A (mass 120kg velocity 5.5m/s [L]) tackles and grabs player B (mass 105kg velocity 7.9m/s [R]). What is the final speed of the two players immediately after the collision?
Answer:
6.62m/s
Explanation:
Given data
M1= 120kg
U1= 5.5m/s
M2= 105kg
U2= 7.9m/s
The system experiences an inelastic collision, the expression for inelastic collision is
M1U1+ M2U1= (M1+M2)V
Subsitute
120*5.5+ 105*7.9= (120+105)*V
660+ 829.5= (225)*V
1489.5= (225)*V
Divide both sides by 225
V= 1489.5/225
V= 6.62m/s
Hence the common velocity is 6.62m/s
what heat transfer occurs when warm air rises
At this point, you have learned that heat is the ________ of ________ energythat is possessed by an object due to the motion of its particles. When this happens, an object’s ____________ changesfrom cool to warmer.There are ways of heat transfer: (a) ____________, where heat is transferred between materials that are in direct contact with each other. While (b) ____________, occurs when heat is transferred by electromagnetic waves (through space). And lastly, (c) ____________is transfer of heat in fluids which makesthe hot fluids to rise and cold fluidstosink
What is this answer? A blank is a combination of two or more substances, elements, compounds, or both, in the same place but not chemically combined