Suppose that the Department of Energy develops a new reversible engine that has a coefficient of performance (COP) of 4.0 when operated as a refrigerator and a COP of 5.0 when operated as a heat pump. What is its thermal efficiency when operated as a heat engine doing work
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%
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.
Two horizontal strings are attached to a block, resting on a frictionless surface as shown
below.A force of 100N pulls on one string. The block does not move. Find the value o
force, F on the other string
ON
Answer:
100N in the opposite direction
Explanation:
as the block is not moving, we can apply the formula f=ma where the total force is equal to the mass times accelaration, since the block is not moving, the net force is zero meaning that the other force is completely cancelling out the force of 100N, or to put it in a maths equation, 100-force=0 as the block is stationary. we can therefore assume that the force cancelling the 100N out is equal to it and therefore 100N in the opposite direction
Someone is not paying attention while speeding down the tramway. Their truck has a mass of 2000 kg. Going a whopping 34.1 m/s (76.3 mph) the truck crashes into a stationary Corolla (mass of 1100 kg). If the truck comes to a complete stop, how fast does the Corolla slide forward when it is hit
Answer:
Explanation:
This question comes from Conservation of Momentum
M1=2000kg
U1=34.1ms^-1
Now this truck crashes into a stationary corolla
Since its stationary
U2=0
M2=1100kg
The Moving Truck came to a complete stop(or rest)
Its Final Velocity V1=0
Mass still remains the same
The corolla will move with a speed V2
Applying the formula for conversation of Momentum
M1U1 + M2U2 = M1V1 + M2V2
2000(34.1) + 1100(0) = 2000(0) + 1100(V2)
2000(34.1) = 1100(V2)
V2 = 2000(34.1)/1100
V2 =62ms^-1
find the cost of running a 60watt for 24hrs. if the electrical energy cost 5 kobo per unit
Answer:
60xtime x cost per unit
Explanation:
...
he electric field is dependent on the distance between the plates. false: The voltage of a connected charged capacitor decreases when the plate area is increased. false: The voltage of a disconnected charged capacitor increases when the plates are brought closer together.
Answer:
False.
Explanation:
The voltage of a disconnected charged capacitor decreases when the plates are brought closer together because the capacitance is inversely proportional to the area. If the area between plates decreases, its capacitance increases and vice versa. There is direct relationship between voltage of a disconnected charged capacitor and plates. If the distance between plates decreases, the voltage of a disconnected charged capacitor is also decreases while on the other hand, if the distance between plates increases, the voltage of a disconnected charged capacitor is also increases.
The table shows the relationship between the masses of two objects, the distance between the two objects, and the gravitational force between the objects. A 4-column table with 5 rows. The first column labeled Mass of Object 1 (kilograms) has entries 1, 2, 2, 3, 9. The second column labeled Mass of Object 2 (kilograms) has entries 1, 1, 2, 3, 3. The third column labeled Distance between Objects 1 and 2 (meters) has entries 1, 1, 2, 1, 3. The fourth column labeled Gravitational Force Objects 1 and 2 (Newtons) has entries 1 G, 2 G, 1 G, 9 G, 3G. Which conclusion is supported by the data in the table? An increase in the mass of an object causes the same decrease in the gravitational force. An increase in the distance between the objects causes the same decrease in the gravitational force. An increase in the distance between the objects causes a greater change in the gravitational force than the same increase in mass. An increase in the mass causes a greater change in the gravitational force than the same increase in the distance between the objects. Brainlyest for correct answer!
Answer:
C
Explanation:
edge 2020... Using elimination it's the only one that makes sense.
The statement third "an increase in the distance between the objects causes a greater change in the gravitational force than the same increase in mass" is correct.
What is gravitational force?The gravitational force is a force that attracts all mass-bearing objects. The gravitational force is referred to as attractive because it always strives to pull masses together rather than pushing them apart.
As we know, the gravitational force is given by:
[tex]\rm F = \dfrac{Gm_1m_2}{r^2}[/tex]
Where, G is the gravitational constant.
m1 and m2 are masses.
r is the distance between the masses.
From the data given in the table, shows that:
The gravitational force is indirectly proportional to the square of the distance.
Thus, the statement third "an increase in the distance between the objects causes a greater change in the gravitational force than the same increase in mass" is correct.
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The first law of thermodynamics (which states that energy is conserved) does not specify the direction in which thermodynamic processes in nature can spontaneously occur.
a. True
b. False
Answer:
a. True
Explanation:
The law of conservation of Energy states that energy cannot be destroyed but can only be converted or transformed from one form to another. Therefore, the sum of the initial kinetic energy and potential energy is equal to the sum of the final kinetic energy and potential energy.
Mathematically, it is given by the formula;
Ki + Ui = Kf + Uf .......equation 1
Where;
Ki and Kf are the initial and final kinetic energy respectively.
Ui and Uf are the initial and final potential energy respectively.
The First Law of Thermodynamics is another way to describe the Law of Conservation of Energy. Typically, the First Law of Thermodynamics states that the change of internal energy of a system is equal to the sum of external work and heat spent on the system.
Mathematically, the First Law of Thermodynamics is given by the formula;
ΔU = Q − W
Where;
ΔU represents the change in internal energy of a system.
Q represents the net heat transfer in and out of the system.
W represents the sum of work (net work) done on or by the system.
Hence, the direction in which any thermodynamic process in nature can spontaneously occur isn't stated by the First Law of Thermodynamics.
laser light sent through a double slit produces an interference pattern on a screen 3.0 m from the slits. If the eighth order maximum occurs at an angle of 12.0, at what angle does the third order maximum occur
Solution :
Given the laser light which is sent through the double slit produces an interference pattern on the screen placed 3 meters from the slits.
The 8th order maximum occurs at angle = 12
So,
[tex]$8^{th} \text{ order maxima} = d \sin \theta = m \lambda$[/tex] , m = 8
[tex]$d = \frac{8 \lambda}{\sin 12}$[/tex]
[tex]$\frac{\lambda}{d}= \frac{\sin 12}{8}$[/tex]
[tex]$3^{rd} \text{ order maxima}= d \sin \theta_2 = m_2 \lambda$[/tex]
[tex]$\sin \theta_2 = \frac{m_2 \lambda}{d}=\frac{3 \lambda}{d}$[/tex] [tex]$=0.75\ {\sin 12}$[/tex]
[tex]$\theta_2 = \sin^{-1}\left(0.75\ \sin 12\right)$[/tex]
[tex]$ = \sin^{-1}\left(0.155)$[/tex]
[tex]$=8.91^\circ$[/tex]
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.
from
Which energy transformation is correct?
O From A to C, kinetic energy is transformed into
gravitational potential energy.
O From C to D, kinetic energy is transformed into
gravitational potential energy.
O From C to E, gravitational potential energy is
transformed into kinetic energy.
O From D to E, gravitational potential energy is
transformed into kinetic energy.
B. The energy transformation that is correct is From C to D, kinetic energy is transformed into gravitational potential energy.
What is law of conservation of energy?The law of conservation of energy states that energy can neither be created nor destroyed but can be transformed from one form to another.
Energy transformation in the pendulum;
At point A, there's only gravitational potential energy and no kinetic energy, because the pendulum is at rest at A. At point C, it has maximum speed since all of the potential energy is transformed into kinetic energy. Therefore, at this point there is only kinetic energy and no potential energy.At point E, it is the same as at point A, but in opposite side. So, at this point there is no kinetic energy.At points B and D there are both kinetic and potential energy. At point B the kinetic energy is increasing and at point D it is decreasing.Thus, the energy transformation that is correct is From C to D, kinetic energy is transformed into gravitational potential energy.
option B is the correct answer.
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Answer:
B is Correct
Explanation:
From C to D, kinetic energy is transformed into gravitational potential energy.
Suppose the spring constant or force constant of the spring is 32.0 N/m and a total of 2.0 kg hangs at the bottom. The mass is smacked upwards from its rest position so that it rises up by 0.40 m before it starts back down. What is the acceleration of the mass at either end of its motion
Answer:
Explanation:
Elongation in the spring when a mass of 2 kg hangs from it
k d = mg where d is the elongation
32 d = 2 x 9.8
d = .6125 m .
When it rises by .40 m , the elongation reduces to .6125 - .40 = .2125 m
upward restoring force at this point = 32 x .2125 = 6.8 N .
Its weight = 2 x 9.8 = 19.6 N acting downwards
Net force on mass of 2 kg = 19.6 - 6.8 N = 12.8 N .
acceleration in downward direction = net force / mass = 12.8 / 2 = 6.4 m/s²
At the bottommost point , total extension = .6125 + .40 = 1.0125 m
restoring force in upward direction = 32 x 1.0125 = 32.4 N .
Net force in upward direction = 32.4 - 19.6 N = 12.8 N
acceleration = 12.8 / 2 = 6.4 m /s² in upward direction .
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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If we had sent a radio signal to an advanced civilization in 2006 which is located in the zeta reticuli star system approximately 39 light-years away, when would the signal arrive at its destination
Answer: 2045
Explanation:
Given
We had sent a radio signal to advance civilization in 2006 which is 39 light-years away i.e. time taken by light to reach reticuli star system is 39 years.
So, it will arrive the destination in the year [tex]2006+39=2045[/tex]
A child is holding a wagon from rolling straight back down in a driveway that inclined at 20 degree horizontal. if the wagon weigh 150n with what force must the child pull on the handle if the handle is parallel to the incline?
Answer:
F = 51.3°
Explanation:
The component of weight parallel to the inclined plane must be responsible for the rolling back motion of the car. Hence, the force required to be applied by the child must also be equal to that component of weight:
[tex]F = Parallel\ Component\ of\ Weight\ of\ Wagon= WSin\theta\\[/tex]
where,
W = Weight of Wagon = 150 N
θ = Angle of Inclinition = 20°
Therefore,
[tex]F = (150\ N)Sin\ 20^o[/tex]
F = 51.3°
on power line, bird can enjoy sitting from one live wire to the other. However,if a person touches it,then the person will die within split seconds. explain this situation
Answer:
Due to potential difference (elaborated in explanation)
Explanation:
When a bird sits on a power line, its whole body is in contact with the power line. It does not have any contact with the ground or anything at a lower potential. Hence, the current does not flow through the bird's body, because there is no potential difference available as a driving force.
Now, when a person touches the power line his hand is at a higher potential provided by the power line, while the rest of his body is connected to the ground, usually through legs. The current always looks for a path from high potential to low potential. Therefore, the body of the person serves as the path for the current. Heavy current flows through the body and the person die within split seconds.
What parts are found in an electric generator? Check all that apply.
Answer:
an armature a permanent magnet brushes slip rings
Explanation:
Answer:
armature, permanent magnet, brushes, slip rings on edge:-)
Explanation:
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)
A cannon at rest fires a 32.5 kg cannonball forward at 388 m/s. After firing, the cannon recoils at 7.42 m/s. What is the mass of the cannon?
(Unit = kg)
Remember: right is +, left is -
Answer:
1700 kg
Explanation:
Let’s use conservation of momentum
32.5 * 388 = 7.42 * mc
mc = 1699.46
mc = 1700 kg
el sistema energético que importancia tiene en el cuerpo
Answer:
De un modo más claro, los sistemas energéticos son los modos que tiene el organismo para suministrar ATP a los músculos. Como decimos, en todos los esfuerzos físicos es necesario contar con la cantidad suficiente de energía y esto viene determinado por la producción de ATP, el adenosin trifosfato.
what do folds on a strip of paper mean
In which of the following forms of energy might you find specially placed tiles on the floor? O A. passive solar O B. geothermal O c. wind power O D. biomass
Answer:
A, Passive Solar.
Explanation:
b) What are the only two sources of energy that produce all the energy we use on Earth? What form
of energy does each of these sources use?
Answer:
Solar and nuclear power generate more than 99 percent of our civilization's energy. Every other important source of energy is a combination of these two. The majority of them are solar in nature. We discharge previously collected solar energy when we burn wood.
and
Nuclear energy, fossil energy (oil, coal, and natural gas), and renewable energy (wind, solar, geothermal, and hydropower) are all examples of primary energy sources.
Explanation:
Which conclusion can be made based on the information in the table? Wave speed and wavelengths can vary inversely to produce the same frequency. Frequency and wave speed can vary directly to produce the same wavelength. Wavelengths and frequency can vary inversely to produce the same wave speed. Frequency and wavelengths can vary directly to produce the same wave speed.
Answer: I think it’s C
Explanation:
On edge.
Answer:
It's (C) Wavelengths and frequency can vary inversely to produce the same wave speed.
The physics of wind instruments is based on the concept of standing waves. When the player blows into the mouthpiece, the column of air inside the instrument vibrates, and standing waves are produced. Although the acoustics of wind instruments is complicated, a simple description in terms of open and closed tubes can help in understanding the physical phenomena related to these instruments. For example, a flute can be described as an open-open pipe because a flutist covers the mouthpiece of the flute only partially. Meanwhile, a clarinet can be described as an open-closed pipe because the mouthpiece of the clarinet is almost completely closed by the reed.
What is the frequency of the first possible harmonic after the fundamental frequency in the open-closed pipe described in Part E?
Part E was What length of open-closed pipe would you need to achieve the same fundamental frequency as the open-open pipe discussed in Part A? Half the length of the open-open pipe.
Part A was Consider a pipe of length 80.0 open at both ends. What is the lowest frequency of the sound wave produced when you blow into the pipe? frequency 214 Hz
Answer:
a) λ = 4L, b) L_c = ½ Lₐ, c) f = 214 Hz
Explanation:
a) in this part, the fundamental frequency (1st harmonic) is requested
In a pipe, the side that is closed has a node and the open side has a belly, so the wavelength inside the pipe is ¼ of the wavelength.
λ = 4L
to find the frequency let's use the definition of velocity
v = λ f
f = v /λ
f = v / 4L
b) in this part let's start by finding the resonance for a tube open at both ends
λ = 2 L
f = v / 2L
since they ask for the same frequency, let's match the two expressions
v / 4L_c = v / 2Lₐ
L_c = ½ Lₐ
therefore the length of the closed tube must be half the length of the open tube
c) It is indicated that the length of the open tube is L = 80 cm = 0.80 m
the frequency is
f = v / 2L
f = 343/2 0.8
f = 214 Hz
a(n) ______ travels at the speed of light
Answer:
flash
Explanation:
Touch light
Explanation:
touch can travel at the speed of light because is a straight line
If an object is placed 10cm in front of a converging lens that has a focal length of 15cm. What are the properties of the image?
Answer:
Enlarged [Size]
Virtual and Erect [Nature]
On the same side of the lens as the object [Position]
Explanation:
Which wavelength is most likely seen as violet light?
anyone know how to do this
A golf club hits a 0.0459 kg golf ball at rest; the club is in contact with the ball for 0.00138 s. Afterwards the ball leaves at 63.9 m/s. How much force acted on the ball? (Unit = N)
Answer: 2120 N is correct
Explanation: correct answer for acellus
