Answer:
η = 0.2 = 20%
Explanation:
The relationship between the thermal efficiency of a heat engine and the Coefficient of Performance (COP) of the corresponding Heat Pump is given as follows:
[tex]\eta = \frac{1}{COP_{HP}}[/tex]
where,
η = thermal efficiency = ?
[tex]COP_{HP}[/tex] = Coefficient of Performance of Heat Pump = 5
Therefore,
[tex]\eta = \frac{1}{5} \\\\[/tex]
η = 0.2 = 20%
Scuba divers carry ballast weights to have neutral buoyancy. At that condition, the buoyancy force on the diver exactly balances weight, and there is no tendency either to float toward the surface or to sink. In freshwater, a certain diver carries 10 lb of lead alloy ballast of density 1.1 x 104 kg/m3. During an excursion in seawater, the diver must carry 50% more ballast to remain neutrally buoyant. How much does this diver weigh
Answer:
732.96 N
Explanation:
In fresh water the diver carries ; 10 Ib of lead alloy = 44.5 N
Ballast density : 1.1 * 10^4 kg/m^3
Diver must carry 59% more ballast in seawater
first step : For fresh water
mass of lead alloy in freshwater
mf = wf /g = 44.5 N / 9.81 = 4.536 kg
Volume of lead alloy ballast in fresh water
Vf = mf / plead
= ( 4.536 ) / ( 1.1 * 10^4 ) = 4.1 * 10^ -4 m^3
Second step : For sea water
mass of alloy in seawater
Ms = Ws / g
Ws = 10 Ib + 5 Ib = 15 Ib = 66.75 N
hence ; Ms = 66.75 / 9.81 = 6.804 kg
Volume of alloy in seawater
Vs = Ms / plead = 6.804 / ( 1.1 * 10^4 ) = 6.2 * 10^-4 m^3
Next : considering the diver in freshwater with Ballast weight
= weight of diver + ballast weight (Wf) = ( pfresh * ( V + Vf ) ) * g ---- ( 1 )
where : pfresh = 1000 kg/m^3 , Vf = 4.1 * 10^-4 m^3, g = 9.81 , Wf = 44.5 N
hence equation 1 becomes
W + 44.5 = 9810 * V + 4.1
W + 40.4 = 9810 V --------------- ( 3 )
Considering Diver in seawater with Ballast weight
weight of diver + ballast weight (Ws) = ( psea * ( V + Vs ) ) * g ---- ( 2 )
where : psea = 1026 kg/m^3 , Vs = 6.2 * 10^-4 m^3 , g = 9.81 , Ws = 66.75 N
equation 1 becomes
W + 66.75 = 10065.06 * V + 6.2
W + 60.55 = 10065.06 V
∴ V = ( W + 60.55 )/ 10065.06 ( Input value into equation 3 to determine the weight of the diver )
W + 40.4 = 9810 ( ( W + 60.55 )/ 10065.06 )
10065.6 ( W + 40.4 ) = 9810 ( W + 60.55 )
10065.6 W - 9810 W = 593995.5 - 406650.24
∴ W ( weight of diver ) = 187345.26 / 255.6 = 732.96 N
Extrusive Igneous rock has ___________ grain size.
I need help on this one
Explanation:
Extrusive rocks may have a few grains that are large enough to see, but most of them will be too small to see individual minerals. ... The individual mineral grains are almost too small to see. Some extrusive rocks cool so quickly that they do not form any grains. Instead, they form a natural glass.
Positive electric charges are always attracted to ________ charges.
Answer:
Negative electric charges
Which exercise type will improve a person's range of motion?
Answer:
stretching prior to an exercise is a great way to improve a range of motion, along with yoga and Pilates!
What happens to matter when it reaches absolute zero?
A. Its particles speed up.
O B. Its particles have no kinetic energy.
O C. Its particles vibrate slightly.
D. Its particles gain kinetic energy.
Explanation:
It will be B.Its particles have no kinetic energy.
What is reflection of light
Answer: When a ray of light approaches a smooth polished surface and the light ray bounces back, it is called the reflection of light. The incident light ray which lands upon the surface is said to be reflected off the surface. The ray that bounces back is called the reflected ray.
Have a great day and stay safe !
The low-frequency speaker of a stereo set produces 10.0 W of acoustical power. If the speaker projects sound uniformly in all directions, at what distance from the speaker is the intensity level 80.0 dB
Answer:
the required distance is 89.125 m
Explanation:
Given the data in the question;
we know that, sound intensity B in decibels of sound is;
β(dB) = 10log₁₀( [tex]I[/tex] / [tex]I_0[/tex] )
where intensity [tex]I[/tex] = power / area carried by wave
[tex]I_0[/tex] = 10⁻¹² W/m² { minimum threshold intensity }
Now,
intensity [tex]I[/tex] = power / area carried by wave = P/A = P/4πr² { spherical }
given that; β = 80.0 dB and P = 10 W
so
β(dB) = 10log₁₀( [tex]I[/tex] / [tex]I_0[/tex] )
we substitute
80 = 10log₁₀( P / 4πr²× [tex]I_0[/tex])
80 = 10log₁₀( 10 / 4πr²× 10⁻¹² )
8 = log₁₀(10) - log₁₀( 4πr²× 10⁻¹² )
8 = 1 - log₁₀( 4πr²× 10⁻¹² )
8 - 1 = -log₁₀( 4πr²× 10⁻¹² )
7 = -log₁₀( 1.2566 × 10⁻¹¹ × r² )
7 = -[ log₁₀( 1.25 × 10⁻¹¹) + log₁₀( r² ) ]
7 = -[ -10.9 + log₁₀( r² ) ]
7 = 10.9 - log₁₀( r² )
-log₁₀( r² ) = 7 - 10.9
-log₁₀( r² ) = - 3.9
log₁₀( r² ) = 3.9
2log₁₀r = 3.9
log₁₀r = 3.9 /2
log₁₀r = 1.95
r = 89.125 m
Therefore, the required distance is 89.125 m
Two particles, with charges of 20.0 nC and -20.0 nC, are fixed at points with coordinates <0, 4.00 cm> and <0, -4.00 cm>. A particle with charge 10.0 nC is fixed at the origin. (a) Find the electric potential energy of the configuration of the three fixed charges. (b) A fourth particle, with a mass of 2.00 x 10-13 kg and charge of 40.0 nC, is released from rest at the point <3.00 cm, 0>. Find its speed after it has moved freely to a very large distance away.
Answer:
Explanation:
Potential energy of the system of charges
= 9 x 10⁹ x [ q₁q₂ / r₁₂ + q₂q₃ / r₂₃ + q₁q₃ / r₁₃ ]
here r₁₂ , r₂₃ , r₁₃ are distance between 1 st and 2 nd charge , 2 nd and 3 rd charge and fist and third charge.
r₁₂ = 8 cm , r₂₃ = 4 cm , r₁₃ = 4 cm.
q₁ = 20 x 10⁻⁹ C , q₂ = - 20 x 10⁻⁹ C , q₃ = 10 x 10⁻⁹ C
Potential energy = 9 x 10⁹ x [ - 400 x 10⁻¹⁸ / .08 + -200x10⁻¹⁸ / .04 + 200 x 10¹⁸ / .04 ]
= 9 x 10⁹ x - 400 x 10⁻¹⁸ / .08
= 45 x 10⁻⁶ J .
b)
Potential at the point of fourth charge due to three charges of 20 nC , - 20 nC and 10 nC at the centre
9 x 10⁹ [ 20 x 10⁻⁹ / .05 + - 20 x 10⁻⁹ / .05 + 10 x 10⁻⁹ / .03 ]
= 9 x 10⁹ x 10 x 10⁻⁹ / .03
= 3000 V .
potential energy of fourth particle = charge x potential
= 3000 x 40 x 10⁻⁹ = 12 x 10⁻⁵ J .
kinetic energy at infinity = 12 x 10⁻⁵ J
1/2 m v² = 12 x 10⁻⁵ J
.5 x 2 x 10⁻¹³ x v² = 12 x 10⁻⁵
v² = 12 x 10⁸
v = 3.46 x 10⁴ m/s
= 9 x 10⁹
I've asked this question 5 times and still no answer pls help TT
What are three ways a driver can cause a car to accelerate?
A. Turn the key in the ignition while the car is stopped.
B. Turn the steering wheel while the car is moving.
C. Press the gas pedal while the car is stopped.
D. Press the brake pedal while the car is moving.
Answer:
c
Explanation:
the gas pedal gives the engine the fuel it needs to give the car the power to go
A pendulum that was originally erected by Foucault at the Pantheon in Paris for the Paris Exhibition in 1851 was restored in 1995. It has a 28.0 kg sphere suspended from a 67.0-m light cable. If the amplitude of the swing is 5.00 m, what is the maximum speed of the sphere
Answer:
13.1 m/s
Explanation: Given that a pendulum that was originally erected by Foucault at the Pantheon in Paris for the Paris Exhibition in 1851 was restored in 1995. It has a 28.0 kg sphere suspended from a 67.0-m light cable. If the amplitude of the swing is 5.00 m, what is the maximum speed of the sphere
The formula to use is :
W = sqrt ( L/g )
Where
L = 67m
g = 9.8m/s^2
A = 5m
Substitute all the parameters into the formula
W = sqrt ( 67 / 9.8 )
W = 2.6
To get the maximum velocity, we use the below formula.
V = wA
V = 2.6 × 5
V = 13.07 m/s
Therefore the maximum speed of the sphere is 13.1 m/s approximately.
The photo shows a person pumping gasoline into a car
Which TWO of these energy transformations will occur when the car’s engine starts?
A. Chemical energy —> thermal energy
B. Chemical energy —> mechanical energy
C. Mechanical energy —> Chemical energy
D. Thermal energy —> chemical energy
Choose TWO
Answer:
A&B
Explanation:
Answer:
Chemical to mechanical(b) and Chemical to Thermal(a)
Which wavelength is most likely seen as violet light?
example of nuclear fission and nuclear fusion
Answer:
In fission, energy is gained by splitting apart heavy atoms, for example uranium, into smaller atoms such as iodine, caesium, strontium, xenon and barium, to name just a few. However, fusion is combining light atoms, for example two hydrogen isotopes, deuterium and tritium, to form the heavier helium.
Explanation:
I hope this helped you
(Sorry If it didn't)
stephen stigler determined in 1977 that the speed of light is 299,710.5 km/sec. in 1882, albert michelson is there enough evidence to show that michelson's data is different from stigler's value of the speed of light? test at 5% level
Answer: hi your question is incomplete attached below is the complete question
answer :
population parameter( μ ) : mean speed of light measured by Albert Michelsonnull hypothesis ( H₀ ) : μ = 299,710.5km/s.Alternate hypothesis ( Hₐ ) : μ ≠ 299,710.5 km/secRandom variable : Speed of light measured by Albert Michelson.Explanation:
Using the information provided in the question attached I will match each term with its corresponding meaning
population parameter( μ ) : mean speed of light measured by Albert Michelson, here the parameter of interest is the speed of light measured/recorded by Albert which is represented as population mean μnull hypothesis ( H₀ ) : μ = 299,710.5km/s. given that the test is to determine if the speed of light recorded by both scientists are the sameAlternate hypothesis ( Hₐ ) : μ ≠ 299,710.5 km/sec. given that the test is to determine if the speed of light recorded by both scientists are the sameRandom variable ( x ) : Speed of light measured by Albert Michelson. her we are trying to bring to conclusion data measured by Albert Michelsong An electron moves on a direction perpendicular to this page, into this page . The arrow below shows the direction of the magnetic field B present in this region. ----------------> B The direction of the magnetic force acting on the electron is directed
Answer:
force on the electron is upwards
Explanation:
The magnetic force is given by the relation
F = q v x B
the bold indicates vectors, we can write the module of this expression
F = q v B sin θ
the direction of the force is given by the right hand rule.
If we have a positive charge, the flea points in the direction of velocity, in this case towards the inside of the page.
fingers extended in the direction of the magnetite field, in our case to the right and
the palm gives the direction of the force for a positive charge, for a negative charge it is in the opposite direction. The palm points downwards, so the force on the electron is upwards
Donna and Dave were participating in a lab on the properties of water. First, they tried to see how many drops of water they could fit on a penny. Then they dropped water and alcohol on waxed paper and observed what happened. Next they made a streak of water and then alcohol on the lab bench. The alcohol streak dried up and disappeared first. Donna and Dave had to write an explanation for everything that happened during the lab. How can they explain the disappearing alcohol? A) Alcohol is flammable. B) Alcohol has a lower boiling point than water. C) Alcohol has a lower melting point than water. D) Alcohol has a higher boiling point than water.
Answer:
D
Explanation:
D ok ok ok ok bye
The correct statement is that the alcohol has lower boiling point than water. The correct option is B.
What is boiling point?At the boiling point, the pressure exerted by the surroundings on a liquid equals the pressure exerted by the liquid's vapor, under this condition, adding heat outcomes in the transformation of the liquid into its vapor without raising the temperature.
The boiling point of alcohol is low. Because there is less hydrogen bonding between ethanol molecules than between water molecules.
The ethanol requires less energy to vaporize than water, and water has a higher boiling point than ethanol.
The boiling point of a liquid can be known by utilizing the capillary method, that encompasses placing an inverted capillary in the liquid of interest as well as heating it.
Thus, the correct option is B.
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A 0.8 kg bead slides on a curved wire, starting
from rest at point A as shown in the figure.
The segment from A to B is frictionless, and
the segment from B to C is rough. The point
A is at height 7.1 m and the point C is at
height 2.5 m with respect to point B.
Find the speed of the bead at B. The acceleration due to gravity is 9.8 m/s2
Answer in units of m/s.
If the bead comes to rest at C, find the change
in mechanical energy due to friction as it
moves from B to C.
Answer in units of J.
a) The speed of the bead at B is 11.79m/s.
b) The change in mechanical energy due to friction as it moves from B to C is 36.064 J.
If we drop the object from the shelf or release the spring, that potential energy is converted back into kinetic energy. Kinetic energy can also be transferred from one body to another in a collision, which can be elastic or inelastic.
a)
Potential energy is converted to kinetic energy
[tex]\frac{1}{2} mv^2=mgh\\\\v=\sqrt{2gh} \\\\v_B=\sqrt{2(9.8)(7.1-0)} \\\\v_B=11.79m/s[/tex]
The speed of the bead at B is 11.79m/s.
b)
[tex]W = mg(h_A) - mg(h_B) = 0.8(9.8)(7.1 - 2.5) = 36.064 J\\\\W=36.064J[/tex]
The change in mechanical energy due to friction as it moves from B to C is 36.064 J.
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During an observation, it was noticed that light diffracts as it passes through small slits in a barrier. What does this evidence reveal about light?
It can travel in various wavelengths.
It can travel through the vacuum of space.
It demonstrates a behavior of energy.
It demonstrates a behavior of waves.
Answer:
It can travel in various wavelengths. brainliest?
Explanation:
The evidence that reveals about the light is that It can travel in various wavelengths.
What is diffraction?
It is the wave property that should be blending of the wave related to the corners.
At the time when the wave is bending so it passed via the openings.
Also, the light diffracted via the small slits and it should be shown to arise in the water waves and the sound waves.
hence, the first option is correct.
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Z. A force that gives a 8-kg objet an acceleration of 1.6 m/s^2 would give a 2-kg object an
acceleration of
a. 0.2 m/s2
b. 0.4 m/s2
c. 1.6 m/s2
d. 6.4 m/s2
Answer:
[tex]\boxed {\boxed {\sf D.\ 6.4\ m/s^2}}[/tex]
Explanation:
We need to find the acceleration of the 2 kilogram object. Let's complete this in 2 steps.
1. Force of 1st ObjectFirst, we can find the force of the first, 8 kilogram object.
According to Newton's Second Law of Motion, force is the product of mass and acceleration.
[tex]F=m \times a[/tex]
The mass of the object is 8 kilograms and the acceleration is 1.6 meters per square second.
m= 8 kg a= 1.6 m/s²Substitute these values into the formula.
[tex]F= 8 \ kg * 1.6 \ m/s^2[/tex]
Multiply.
[tex]F= 12.8 \ kg*m/s^2[/tex]
2. Acceleration of the 2nd ObjectNow, use the force we just calculated to complete the second part of the problem. We use the same formula:
[tex]F= m \times a[/tex]
This time, we know the force is 12.8 kilograms meters per square second and the mass is 2 kilograms.
F= 12.8 kg *m/s²m= 2 kgSubstitute the values into the formula.
[tex]12.8 \ kg*m/s^2= 2 \ kg *a[/tex]
Since we are solving for the acceleration, we must isolate the variable (a). It is being multiplied by 2 kg. The inverse of multiplication is division. Divide both sides of the equation by 2 kg.
[tex]\frac {12.8 \ kg*m/s^2}{2 \ kg}= \frac{2\ kg* a}{2 \ kg}[/tex]
[tex]\frac {12.8 \ kg*m/s^2}{2 \ kg}=a[/tex]
The units of kilograms cancel.
[tex]\frac {12.8}{2}\ m/s^2=a[/tex]
[tex]6.4 \ m/s^2=a[/tex]
The acceleration is 6.4 meters per square second.
Questions on the photo
Answer:
Option C: Third Class
Explanation:
This is third class because the effort or the input force is in the middle between the fulcrum and the load.
To solve this, we must be knowing each and every concept related to lever. Therefore, due to the effort or input force being in the center between the edge as well as the load, the supplied lever is of 3rd class. The correct option is option C.
What is lever?A lever is a basic device that consists of a beam or stiff rod located at a set tight, or edge. It is used to apply force to a load and often offers a mechanical advantage.
A stiff object that can rotate about a spot on itself is called a lever. The three types of levers are categorized according to where the edge, weight, and effort are located. Due to the effort or input force being in the center between the edge as well as the load, the supplied lever is of 3rd class.
Therefore, the correct option is option C.
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A double-slit interference pattern is created by two narrow slits spaced 0.25 mm apart. Thedistance between the first and the fifth minimum on a screen 60 cm behind the slits is 5.5mm. What is the wavelength (in nm) of the light used in this experiment
Answer:
Explanation:
Slit distance d = .25 x 10⁻³ m .
Distance of screen D = 60 x 10⁻² m
Distance between first and fifth minimum = 5.5 x 10⁻³ m .
There will be four bright fringes between first and 5 th minimum so
distance between them = 4 x λ D / d where λ is the wavelength of light .
Substituting the values
4 x λ x 60 x 10⁻² m / .25 x 10⁻³ m = 5.5 x 10⁻³ m
4 x λ x 60 x 10⁻² m = .25 x 10⁻³ m x 5.5 x 10⁻³ m = 1.375 x 10⁻⁶ m
λ = .005729 x 10⁻⁴
= 572.9 x 10⁻⁹ m
= 572.9 nm .
A box has a mass of 3 kg. The box is lifted from the floor and placed
on a shelf. If the box gains a Potential Energy of 100 J, then how high
is the shelf?
a 2.34 m
b 1.20 m
C 1.50 m
d 3.40 m
HALP
Explanation:
Potential energy=MGH
100=3×10×H.
H=100/30
H=3.40m
5. Which of the following is velocity? *
2 points
A. 20 m/s
B. 40 m/s east
C. 40 m
D. 20 m
A 1.2-kg mass is projected from ground level with a velocity of 31.3 m/s at some unknown angle above the horizontal. A short time after being projected, the mass barely clears a 16-m tall fence. Disregard air resistance and assume the ground is level. What is the kinetic energy of the mass as it clears the fence
Answer:
The kinetic energy will be "399.65 J".
Explanation:
Given:
Mass,
m = 1.2 kg
Velocity,
v = 31.3 m/s
The total energy of mass will be:
⇒ [tex]E=K+U[/tex]
or,
⇒ [tex]E=.5mv^2+mgh[/tex]
By putting the values, we get
[tex]=.5(1.2)(31.3)^2+0[/tex]
[tex]=0.6\times 979.69+0[/tex]
[tex]=587.81 \ J[/tex]
Since,
The system's total energy is unchanged, then
⇒ [tex]E=K+U[/tex]
or,
⇒ [tex]E=K+mgh[/tex]
[tex]587.81=K+1.2(9.8)(16)[/tex]
[tex]587.81=K+188.16[/tex]
[tex]K=587.81-188.16[/tex]
[tex]=399.65 \ J[/tex]
A grassland ecosystem (ecosystem X) supports 13 different grass species. A different grassland ecosystem (ecosystem Y) supports just one species of grass. Bison graze on all of the grass species in both of these ecosystems. Ecosystem X 13 species of grass Ecosystem Y 1 species of grass A drought strikes both ecosystem X and ecosystem Y, but the bison in ecosystem X are better able to survive it. Which of the following is a likely explanation? A. The bison in ecosystem X only eat one species of grass. B. Ecosystem Y has a greater amount of biomass. C. Ecosystem X has a greater amount of biodiversity. D. Ecosystem Y has a greater amount of biodiversity.
Answer:
Explanation:
Choices are:
A. The bison in ecosystem X only eat one species of grass.
B. Ecosystem Y has a greater amount of biomass.
C. Ecosystem X has a greater amount of biodiversity.
D. Ecosystem Y has a greater amount of biodiversity.
If grass species are drought-resistant, then they will allow the bison to continue feeding on them. X has more species (13) so it is more likely to have some drought-resistant grass.
Answer is C. Ecosystem X has a greater amount of biodiversity.
The bison in ecosystem X are better able to survive the drought because ecosystem X has a greater amount of biodiversity. Option (C) is correct.
What is biodiversity?Biodiversity is the variety of living things found in various habitats, such as terrestrial, marine, and desert ones, as well as the ecological groups to which they belong.
The variety of creatures present in an ecosystem, as well as their relative abundances, is referred to as biodiversity. It also depicts the various stages of organismal organization.
In ecosystem X, 13 different grass species present and in ecosystem Y 1 species of grass present, that is, ecosystem X has a greater amount of biodiversity. So, during the drought, the bison in ecosystem X are better able to survive.
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Ablock of mass m2 on arough horinzontal surfaceis connected to aball of mass m1 by alight weight cord over alight weight friction pulley as shownin figure .aforce of magnitude f at an angle
A 3 Volt battery is connected in series to three resistors: 4,6, and 2. Find the total resistance.
Answer:
The same current flows through each resistor in series. Individual resistors in series do not get the total source voltage, but divide it. The total resistance in a series circuit is equal to the sum of the individual resistances: RN(series)=R1+R2+R3+…
En un viaje ida y vuelta de 10 kilómetros, el desplazamiento y la distancia recorrida son respectivamente.
(Respuestas en la imagen)
Answer: creo que es A o D
Explanation:
A car battery dies not so much because its voltage drops, but because chemical reactions increase its internal resistance. A good car battery typically has a terminal voltage of about 12.5 V and an internal resistance of about 0.020 Ω. When the battery dies its voltage can drop slightly, let's say it drops to about 10.1 V and the internal resistance increases to around 0.100 Ω.
Required:
a. How much current could the good battery alone drive through the starter motor?
b. How much current is the dead battery alone able to drive through the starter motor?
Answer:
(a) I = 625 A
(b) I = 101 A
Explanation:
The relationship between current, voltage and resistance can be given by Ohm's Law:
V = IR
where,
V = Voltage
I = Current
R = Resistance
(a)
Here,
V = 12.5 V
R = 0.02 Ω
Therefore,
[tex]12.5\ V = I(0.02\ \Omega)\\\\I = \frac{12.5\ V}{0.02\ \Omega}[/tex]
I = 625 A
(b)
Here,
V = 10.1 V
R = 0.1 Ω
Therefore,
[tex]10.1\ V = I(0.1\ \Omega)\\\\I = \frac{10.1\ V}{0.1\ \Omega}[/tex]
I = 101 A
what do folds on a strip of paper mean