Answer:
The coefficient of performance of the refrigerator is 2.251.
Explanation:
In this case, the coefficient of performance of the refrigerator ([tex]COP[/tex]), no unit, is equal to the ratio of the heat rate received from the water to the power needed to work, that is:
[tex]COP = \frac{\dot Q_{L}}{\dot W}[/tex] (1)
[tex]COP = \frac{\rho\cdot V\cdot c_{w}\cdot \Delta T}{\dot W \cdot \Delta t}[/tex] (2)
Where:
[tex]\dot Q_{L}[/tex] - Heat rate received from the water, in watts.
[tex]\dot W[/tex] - Power, in watts.
[tex]\rho[/tex] - Density of water, in kilograms per cubic meter.
[tex]V[/tex] - Volume of water, in cubic meters.
[tex]c_{w}[/tex] - Specific heat of water, in joules per kilogram-degree Celsius.
[tex]\Delta T[/tex] - Temperature change, in degrees Celsius.
[tex]\Delta t[/tex] - Cooling time, in seconds.
If we know that [tex]\rho = 1000\,\frac{kg}{m^{3}}[/tex], [tex]V = 1.45\times 10^{-3}\,m^{3}[/tex], [tex]c_{w} = 4187\,\frac{J}{kg\cdot ^{ \circ}C}[/tex], [tex]\Delta T = 10\,^{\circ}C[/tex], [tex]\dot W = 10.7\,W[/tex] and [tex]\Delta t = 2520\,s[/tex], then the coefficient of refrigeration of the refrigerator is:
[tex]COP = \frac{\rho\cdot V\cdot c_{w}\cdot \Delta T}{\dot W \cdot \Delta t}[/tex]
[tex]COP = 2.251[/tex]
The coefficient of performance of the refrigerator is 2.251.
(Click the picture)
What is the source of energy that will send the arrow flying toward the target?
A- The archers ability to aim correctly
B- The arrow’s distance from the ground
C- The springiness of the bow
D- The time it takes to release the bow
Answer:
a
Explanation:
cause her hand is straight and she followed the direction it sould be correctly unless I am messing something
Question 2
Any electricity charged object creates an electric field. Walking across carpet in wool socks can create an electric charge. This
observation is evidence for which characteristics of electrical forces?
They generate electricity by contact.
They can be generated by electricity.
OOO
They can exert a force across a distance.
They are moving due to magnetism.
Answer:
They generate electricity by contact.
Explanation:
The observation presented by the question above shows an example of electricity generated by the contact, which can also be called triboelectrification. This type of electricity is created when two objects made of different materials come into contact with each other, and that contact is interrupted soon afterwards, as occurs when someone, wearing woolen socks, walks over the carpet.
For triboelectrification to occur, it is necessary that at least one of the objects involved is electrically charged. This object, when in contact with another object, will transfer electrons carrying the neutral object, until the two objects have the same electrical potential. When interrupting the contact between the objects, the two are left with equal loads of energy.
A man supports himself and the uniform horizontal beam pulling the rope with a force T.The weights of men and the beam are 883 N and 245 N respectively.Calculate the tension T in the rope and the forces exerted by the pin at A.
Answer:
T=502.5N
Ax=171.8N
Explanation:
The computation of the tension T in the rope and the forces exerted by the pin at A is shown below:
vertical forces sum = Ay + Tsin20 + T - 245 - 883 = 0
Now
horizontal forces sum = Ax - Tcos70
Now Moment about B
-Ay × 4.8 + 245 × 2.4 + 883 × 1.8=0
Ay=453.6N
Now substitute in sum of vertical forces T=502.5N
Ax=171.8N
a. The tension (T) in the rope is equal to 502.51 Newton.
b. The forces exerted by the pin at A is equal to 171.86 Newton.
Given the following data:
Weight of men = 883 N Weight of beam = 245 NTo calculate the tension (T) in the rope and the forces exerted by the pin at A:
First of all, we would determine the vertical force by taking moment about point B as shown in the diagram.
[tex]-A_y \times 4.8 + 883 \times 1.8 + 245 \times 2.4 =0\\\\-4.8A_y + 1589.4 + 588 =0\\\\4.8A_y= 3237\\\\A_y=\frac{2177.4}{4.8} \\\\A_y= 453.63 \;Netwon[/tex]
The tension (T) in the rope would be calculated by the sum of the vertical component of forces, which is given by:
[tex]\sum F_x = A_y + Tsin20 + T - 245 - 883 = 0\\\\453.63 + 0.3420T + T -1128=0\\\\1.3420T = 1128-453.63\\\\1.3420T =674.37\\\\T =\frac{674.37}{1.3420}[/tex]
Tension, T = 502.51 Newton.
To find the forces exerted by the pin at A, we sum the vertical component of forces, which is given by:
[tex]\sum F_y = A_x - Tcos70 =0\\\\A_x =Tcos70\\\\A_x = 502.51 \times cos70\\\\A_x = 502.51 \times 0.3420\\\\A_x = 171.86\;Newton[/tex]
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2.
Which of the following has the greatest momentum?
A.
0.2 kg ball moving at 40 m/s
В.
500 kg car traveling at 16 m/s
С.
2000 kg truck traveling at 9 m/s
D
50 kg child skateboarding at 4 m/s
Answer:
I'm corona positive and isolated feeling depressed just logged in to talk someone but people ignoring me thanks for this behaviour got disappointed bye everyone logging out had a great time
A football thrown by a professional quarterback goes farther than one thrown by a 10-year old. What Newton Law is this?
Answer:
2nd law of motion
Explanation:
Answer:
Newton's 2nd Law of Motion
Explanation:
The amount of force needed to make an object change its acceleration depends on the mass of the object. In other words, the amount of force thrown by a professional quarter-back has more acceleration from his mass.
Is Algae Biotic or Abiotic?
A cylindrical, 0.500-m rod has a diameter of 0.02 m. The rod is stretched to a length of 0.501 m by a force of 3000 N. What is the Young's modulus of the material?
Answer:
Y = 4.775 x 10⁹ Pa = 4.775 GPa
Explanation:
First, we calculate the stress on the rod:
[tex]stress = \frac{Force}{Area} = \frac{3000\ N}{\pi r^2} \\\\stress = \frac{3000\ N}{\pi (0.01\ m)^2}\\\\stress = 9.55\ x\ 10^6\ Pa = 9.55 MPa\\[/tex]
Now, we calculate the strain:
[tex]strain = \frac{Change\ in Length}{Original\ Length}\\\\strain = \frac{0.501\ m - 0.5\ m}{0.5\ m}\\\\strain = 0.002\\[/tex]
Now, we will calculate the Young's Modulus (Y):
[tex]Y = \frac{stress}{strain}\\\\Y = \frac{9.55\ x\ 10^6\ Pa}{0.002} \\[/tex]
Y = 4.775 x 10⁹ Pa = 4.775 GPa
Geronimo wants to move an object 12 meters. Calculate the net work done by the object with an applied force of 150 N and a friction force of 37 N.
Answer:
1476 J
Explanation:
From the question,
Net Work done = Net force× distance moved by net force.
W' = (F-F')×d................... Equation 1
Where W' = Net work done, F = force applied, F' = Frictional force, d = distance moved.
Given: F = 150 N, F' = 37 N, d = 12 m
Substitute these values into equation 1
W' = (150-37)×12
W' = 123×12
W' = 1476 J.
hence the Net Work done by the object is 1476 J
how many nucleons does sulphur have
Answer:
32
Explanation:
Answer:
32
Explanation:
Sulfur has 16 protons and 16 neutrons. The atomic number is roughly 32. Therefore, 16 + 16 = 32 nucleons.
The resistance of resistor is greater for:
a.Short and thin resistor
b.Short and thick resistor
c.Long and thin resistor
d.None
Answer:
c: long and thin resistor.
Explanation:
The resistance of a resistor is given by:
R = ρ*L/A
where:
R = resistance
ρ = resistivity (depends on the material)
L = length of the material
A = cross-sectional area of the material
We can see that the length is on the numerator, which means that if we increase the length, then the resistance is increased.
We also can see that the cross-sectional area is on the denominator, then if we increase the area (for example, with a ticker resistor) the resistance decreases.
Then if we want to maximize the resistance, we need to have a long and thin resistor, so the correct answer is c.
Two charges, one with a charge of +10.0 x 10-6 C, the other with a charge of -3 x 10-6 C exert a force on each other with a magnitude of 1.7 Newtons on each other. Is this a repulsive or attractive force. What is the separation distance of these charges?
Answer:
b.
Explanation:
Answer:
Attractive force and r = 0.399 m
Explanation:
One charge is positive and the other charge is negative. Opposite charges attract, so there has to be a force that attracts between them.
q1 = 10.0 x 10^-6 C
q2 = -3 x 10^-6 C
F = 1.7 N
Plug those values into Coulomb's Law:
[tex]F = k\frac{q1q2}{r^{2} } \\1.7 = \frac{(9x10^{9})(10.0 x 10^{-6})(-3 x 10^{-6})}{r^{2} }[/tex]
Solve for r
r = 0.399 m
The mean orbital radius of the earth around the sun 1.5 × 108 km. Calculate the
mass of the sun if G = 6.67 × 10-11 Nm2/kg -2?
Answer:
M = 1.994 × 10^(30) kg
Explanation:
We are given;
Orbital radius; r = 1.5 × 10^(8) km = 1.5 × 10^(11) m
Gravitational constant; G = 6.67 × 10^(-11) N.m²/kg²
If the orbit is circular, the it means the gravitational force is equal to the centripetal force.
Thus; F_g = F_c
GMm/r² = mv²/r
Simplifying gives;
GM/r = v²
M = v²r/G
Now, v is the speed of the earth around the sun and from online sources it has a value of around 29.78 km/s = 29780 m/s
Thus;
M = (29780^(2) × 1.5 × 10^(11))/6.67 × 10^(-11)
M = 1.994 × 10^(30) kg
Tell me what the laws of thermodynamics are in a simple way
Answer:
The first law, also known as Law of Conservation of Energy, states that energy cannot be created or destroyed in an isolated system. The second law of thermodynamics states that the entropy of any isolated system always increases. The third law of thermodynamics states that the entropy of a system approaches a constant value as the temperature approaches absolute zero.
Explanation:
2) What are the two main types of waves?
Answer:
The two types of waves are longitudinal and transverse
Explanation:
hope it helped! and i hope its correct
what is the net force of a force of 6N going left towards the object and the 8N going to the right towards the object
The net force when a force of 6N going left towards the object and the 8N going to the right towards the object is found to be 2N toward the right of an object.
What is the net force?Net force may be dfeined as the sum of all of the forces acting on an object. It is categorized as a vector quantity because it has both direction and magnitude to be considered.
Net force in a case where forces of different magnitude and opposite directions will be the difference between greater and lesser force. The combination of the resultant of all the forces acting on an object is called Net Force, which is basically the sum of all the forces acting on that object.
According to the question,
The force going towards the left of an object = 6N.
The force going towards the right of an object = 8N.
The net force = 8 - 6 = 2N towards the right of an object.
Therefore, the net force when a force of 6N going left towards the object and 8N going to the right towards the object is found to be 2N toward the right of an object.
To learn more about Net force, refer to the link
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A car traveling at 60km/h undergoes uniform acceleration at a rate of 2/ms^2 until is velocity reached 120km/h determine the distance traveled and the time taken to make the distance
Explanation:
Given that,
Initial speed of a car, u = 60 km/h = 16.67 m/s
Acceleration, a = 2m/s²
Final speed, v = 120 km/h = 33.33 m/s
We need to find the distance traveled and the time taken to make the distance.
acceleration = rate of change of velocity
[tex]a=\dfrac{v-u}{t}\\\\t=\dfrac{v-u}{a}\\\\t=\dfrac{33.33 -16.67 }{2}\\\\t=8.33\ s[/tex]
let the distance be d.
[tex]d=\dfrac{v^2-u^2}{2a}\\\\d=\frac{33.33^{2}-16.67^{2}}{2(2)}\\\\d=208.25\ m[/tex]
Hence, the distance traveled and the time taken to make the distance is 208.25 m and 8.33 seconds respectively.
Through which of the following ways does the Sun primarily transfer its heat energy to the Earth?
A.
conduction
B.
radiation
C.
convection
D.
reflection
Answer:
B. Radiation
Explanation:
Transfer of heat energy through space by electromagnetic radiation
Which of the following statements are true about conduction? Select all that apply. *
-In most solids, conduction takes place as particles vibrate in place.
-Matter is transferred great distances during conduction.
-Thermal energy is transferred without transfer of matter.
-Conduction can occur between materials that are not touching.
Answer:
Matter is transferred great distances during conduction. (t think i'm not truly sure)
Explanation:
The direct transfer of energy from one molecule to another is known as conduction. Conduction occurs in solids, liquids, and gases, but it is most effective in solids. Heat transfer by radiation, unlike conduction or convection, does not require any matter.
hope this helps
According to the concept of conduction,matter is transferred great distances during conduction.
What is conduction?Conduction is defined as a process as a means of which heat is transferred from the hotter end of the body to it's cooler end.Heat flows spontaneously from a body which is hot to a body which is cold.
In the process of conduction,heat flow is within the body and through itself.In solids the conduction of heat is due to the vibrations and collisions of molecules while in liquids and gases it is due to the random motion of the molecules .
When conduction takes place, heat is usually transferred from one molecule to another as they are in direct contact with each other.There are 2 types of conduction:1) steady state conduction 2) transient conduction.According to the type of energy conduction is of three types:
1) heat conduction
2) electrical conduction
3)sound conduction
Learn more about conduction,here:
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it took 500 n of force to push a car 4 meters. how much work was done?
Answer:
2000J
Explanation:
The formula for work is W=Force x Distance
W=FxD
W=500N x 4m
W=2,000 Joules
Two identical charged pith balls are brought together to touch each other. They are then
allowed to move freely. The charge on pith ball A is –30 nC and on pith ball B is – 5 nC.
What is the charge on each after they separate?
Answer:
-17.5 nC
Explanation:
charge A = -30 nC
charge B = -5 nC
After adding them it would be the average of the two charges because of the getting same voltage difference. so
c = (-30+(-5)) / 2 nC
c= -17.5 nC
answer is -17.5 nC
explain the differences between pitch and loudness and what are they connected to?
Answer:
Loudness and pitch are distinct properties of sound. Loudness is related to the amplitude of the sound wave; pitch is related to its frequency
Explanation:
How is capacitance related to the distance between the plates of a capacitor?
It is directly proportional, so the capacitance increases as the distance increases.
It is inversely proportional, so the capacitance increases as the distance increases.
It is directly proportional, so the capacitance decreases as the distance increases.
It is inversely proportional, so the capacitance decreases as the distance increases.
Answer:C
Explanation: I studied, and C is correct
Answer:
D
Explanation:
A student watches as a trash can lid moves across a yard. Which of these could have caused the trash can lid to move?
Answer:
wind energy
Explanation:
Wind energy can be defined as a form of a solar energy. It is generated by the immense force of the wind that blows in an area. Wind energy is a useful energy and is mostly used to generate electricity. It is clean source of energy.
In the context, trash can lid is being blown away by the wind energy and it is seen moving across the yard. The energy of the wind forces the lid of the trash can to move from one place to another against friction. Thus, wind energy caused the trash can lid to move across the yard as seen by a student.
It would not be economical to connect the houses to the National Grid.Give one reason why.
A fluorescent lamp is 25% efficient. Choose the statement that correctly
describes how the lamp performs.
A ) the lamp only works for a quarter of the time
B ) 25% of the electrical energy transferred to the lamp is wasted
C ) the lamp does not work properly
D) 25% of the energy supplied to the lamp is transferred to light
Please answer correctly
Please do not answer from links
Please help
Urgent !!
Will give the brainliest!
Answer:
Explanation:
it's D b/c only 25% of the energy is making light... the rest is probably heat.. :/
You push on a 30 kg box with a force of 120 N. What is the acceleration of the box2
Answer:
6
Explanation:
120/30=6
The water droplets appear to be causing patterns of black and bright blue fringes. in terms of water in the real world (in a bowl, sink or pond), what do the bright blue and black colors mean?
Answer:
The bright blue and black colors represent the following:
Constructive and destructive interference are represented by the blue and black colors, respectively. When two water waves collide constructively, the resultant wave is bright blue, while when they collide destructively, the resultant wave is black in color.
Explanation:
When two propagating waves with the same frequency (say, [tex]\nu[/tex]) and wavelength (say,[tex]\lambda[/tex]) but slightly different amplitudes (say, A 1 and A 2) traveling in the same direction interfere or are superimposed on each other (that is incident at the same point or object), a third resultant wave with a different amplitude (increased or decreased) but same wavelength and frequency is generated.
The direction difference between the two waves determines whether they intervene constructively (increasing the amplitude of the resultant wave) or destructively (increasing the amplitude of the resultant wave) (decreased amplitude of the resultant wave). To put it another way, when the difference in direction between the two waves is of the form -
[tex]\Delta x = n\lambda , n=0,1,2,.....[/tex] is the order of interference.
The two waves are then assumed to be in phase, and the interference is constructive, resulting in the resultant wave having a larger amplitude (which is the sum of the two amplitudes [tex]A_1 +A_2[/tex] also known as a maxima). When the difference in direction between the two waves is in the form -
[tex]\Delta x = (2n-1)\frac{\lambda}{2} , n=0,1,2,.....[/tex] is the order of interference.
The two intervening waves are then said to be out of phase, and the interference is disruptive, resulting in the resultant wave having a lower amplitude (which is the difference between the two amplitudes [tex]A_1+A_2[/tex], also known as a minima).
Hence , the graphical representation of constructive (blue )and destructive (black) is attached.
skier accelerates down the hill at a speed of 18 and reaches the bottom of the hill at a speed of 36 in 6 seconds
What an acceleration of the skier
Answer:
3 m/s²
Explanation:
Initial Velocity, u = 18
Final velocity, v = 36
Time, t = 6 seconds
Acceleration is the change in velocity of a body with time. It obtained using the relation :
Acceleration = (v - u) / t
Acceleration = (36 - 18) / 6
Acceleration = 18 / 6
Acceleration = 3m/s²
Hence, acceleration of the skier is 3m/s²
Resultant vector of a force gives us information regarding ___________ of resultant force.
Answer: direction
Explanation:
Given
The resultant vector of a force gives us information regarding the direction of the resultant force.
If there are multiple forces acted in a different direction then, the resultant vector describes the direction of the resultant force.
True or False: A balanced force acts on different objects, and action-
eaction forces act on the same object. *
A. True
B. False
Answer:
true
Explanation:
according to the Newton's third law