what did the greeks study amber with?
Answer:
The Greeks used static electricity to study amber.
The questions are
1. How much heat is needed to melt 10.0kg of lead at it’s melting point?
2. How much heat is needed to vaporize 10.0 kg of mercury at its boiling point?
3. A temperature of a 0.25 kg sample of copper decreases from 75.0 degrees Celsius to 25.0 degrees Celsius. How much heat flows out of the copper sample?
4. When 8,000 joules of heat are removed from a sample of mercury, the temperature of the sample is decreased from 40 degrees celsius to 15 degrees celsius. what is the mass of the sample?
5. Thermal energy of a substance is the sum of the potential energy and kinetic energy of the particles that make it up. Let’s say you had a hot cup of water and a cold cup of water, then mixed them. Illustrate the behavior of the particles before and after thermal equilibrium is reached
1. [tex]2.3\cdot 10^5 J[/tex]
The amount of heat needed to melt a substance at its melting point is:
[tex]Q=m\lambda_f[/tex]
where
m is the mass of the substance
[tex]\lambda_f[/tex] is the latent heat of fusion of the substance
For the sample of lead in this problem,
m = 10.0 kg
[tex]\lambda_f = 23000 J/kg[/tex] (latent heat of fusion of lead)
Substituting,
[tex]Q=(10.0 kg)(23000 J/kg)=2.3\cdot 10^5 J[/tex]
2. [tex]2.96\cdot 10^6 J[/tex]
The amount of heat needed to evaporate a substance at its boiling point is:
[tex]Q=m\lambda_v[/tex]
where
m is the mass of the substance
[tex]\lambda_v[/tex] is the latent heat of vaporization of the substance
For the sample of mercury in this problem,
m = 10.0 kg
[tex]\lambda_v = 2.96\cdot 10^5 J/kg[/tex] (latent heat of vaporization of mercury)
Substituting,
[tex]Q=(10.0 kg)(2.96\cdot 10^5 J/kg)=2.96\cdot 10^6 J[/tex]
3. [tex]-4875 J[/tex]
The amount of heat released from the sample of copper is
[tex]Q=m C_s \Delta T[/tex]
where
m = 0.25 kg is the mass of the sample
[tex]C_s = 390 J/kg C[/tex] is the specific heat of copper
[tex]\Delta T = 25.0^{\circ}C - 75.0^{\circ}C=-50.0^{\circ}[/tex] is the change in temperature of the copper
Substituting the values into the formula, we find:
[tex]Q=(0.25 kg)(390 J/kg C)(-50.0^{\circ}C)=-4875 J[/tex]
And the negative sign means the heat has been released by the substance.
4. 2.29 kg
Similarly to the previous part, the amount of heat released from the sample of mercury is
[tex]Q=m C_s \Delta T[/tex]
where in this problem we know
m is the mass of the sample
[tex]C_s = 140 J/kg C[/tex] is the specific heat of mercury
[tex]\Delta T = 15.0^{\circ}C - 40.0^{\circ}C=-25.0^{\circ}[/tex] is the change in temperature of the sample
Q = -8,000 J is the heat released by the sample
Solving the formula for m, we find:
[tex]m=\frac{Q}{C_s \Delta T}=\frac{-8000 J}{(140 J/kg C)(-25.0^{\circ})}=2.29 kg[/tex]
5.
When the two samples of water (hot water and cold water) are put in contact, thermal energy is transferred from the hot water to the cold water. This occurs because heat always flows from a hotter object to a colder object. The heat is transferred by collision between the molecules: the molecules of the hot water have on average more kinetic energy than the molecules of cold water, so when they collide to each other, the molecules of hot water transfer energy to the molecules of cold water. As a result, the kinetic energy of the molecules of cold water increases, and therefore the temperature of the cold water increases, while the temperature of the hot water decreases. This process lasts until the molecules of the two samples have same average kinetic energy: when this occurs, the two samples have same temperature, so the heat flow stops.
Answer:
1.Heat needed to melt [tex]10.0[/tex]kg of lead is [tex]$2.3 \cdot 10^{5}$[/tex]J.
2. Heat needed to vaporize [tex]10.0[/tex]kg of mercury is [tex]$2.96 \cdot 10^{6}$[/tex]J.
3.The heat which flows out of the copper sample is [tex]$-4875[/tex]J.
4.The behavior of the particles before and after thermal equilibrium reached is as the temperature of the hot and cold water remains constant for some time.
Explanation:
1. To find the heat needed to melt lead at its melting point is given by a formula,
[tex]$Q=m \lambda_{f}$[/tex]
As,
[tex]\lambda_{f}$=[/tex]Latent heat of the substance
[tex]m=[/tex]Mass of the substance
Given,
mass of lead[tex]=10.0[/tex]kg
We know that,the latent heat of lead is [tex]$23000 $[/tex] J/kg
So apply in formula,
[tex]$Q=(10.0 k g)(23000 J / k g)$[/tex]
[tex]=$2.3 \cdot 10^{5}$J[/tex].
2. To find, heat needed to vaporize mercury at its boiling point is given by a formula,
[tex]$Q=m \lambda_{v}$[/tex]
As,
[tex]$ \lambda_{v}=$[/tex]Latent heat of the substance.
[tex]m=[/tex]mass of the substance.
Mass of mercury[tex]=10.0[/tex]kg
We know that,the latent heat of Mercury is [tex]$2.96 \cdot 10^{5}$[/tex]J/kg
Apply in formula,
[tex]$Q=(10.0 \mathrm{~kg})\left(2.96 \cdot 10^{5} \mathrm{~J} / \mathrm{kg}\right)[/tex]
[tex]=2.96 \cdot 10^{6} $[/tex]J.
3. The amount of heat released from the sample of copper given by,
[tex]$Q=m C_{s} \Delta T$[/tex]
In this,
[tex]m=[/tex]Mass of the copper sample
The specific heat of mercury,
[tex]$C_{s}=140 \mathrm{~J} / \mathrm{kgC}$[/tex]
Change in temperature of copper sample,
[tex]$\Delta T=15.0^{\circ} \mathrm{C}-40.0^{\circ} \mathrm{C}[/tex]
[tex]=-25.0^{\circ}$[/tex]
Also we know that,
[tex]$Q=-8,000 \mathrm{~J}$[/tex]
Mass value is as,
[tex]$m=\frac{Q}{C_{s} \Delta T}$[/tex]
Apply the value in formula we get,
[tex]$=\frac{-8000 . J}{(140 J / \mathrm{kgC})\left(-25.0^{\circ}\right)}[/tex]
[tex]=2.29 \mathrm{~kg}$[/tex].
4. The behavior of the particles before and after thermal equilibrium,
When we mix the hot cup of water and a cold cup of water, the molecules from hot water transters to cold water due to thermal energy.As collision between hot and cold water occurs,this collision is due to kinetic energy.Hence,the kinetic energy of the molecules of cold water increase,the temperature of the cold water also increase but kinetic energy in hot water decreases due to collision.When the kinetic energy of hot and cold water becomes equal,the temperature of the hot and cold water remains same for some time.Learn more about energy and particles,
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1.3.2 Quiz: Inspiration for Independence
Question 3 of 10
2 Points
What idea in the Declaration of Independence reflects the influence of John
Locke?
Answer:
The ideas in the Declaration of Independence that reflect the influence of John Locke are the following:
People are entitled to certain unalienable rights.The government had to protect those rights.The government’s legitimacy comes from the consent of the governed and it had to be accountable for the people.Whenever a government failed to protect people's fundamental rights, it had to be abolished and replaced.Explanation:
The Declaration of Independence was highly influenced by Enlightenment ideas, especially those ideas developed in John Locke's "Two Treatises of Government" (1689).
In this work, Locke claimed that men were by nature free and equal, but with the purpose to interact in a healthy society, it was necessary that they transferred some of their rights to a government in a "Social Contract". Under that contract, the government had to be elected by the people and had to protect people's natural rights to life, liberty, and property. However, whenever the government failed to do so, people had the authority to abolish it and replace it.
Similarly, in the Declaration of Independence, the Thirteen American colonies unanimously declared independence from Britain for violating the social contract, that is, for not securing people's unalienable rights of Life, Liberty and the pursuit of Happiness (The latter being a concept said to be taken out from one of the others Locke's work). In the document, the colonies also favored a limited government whose power came from the consent of the governed and that had to be accountable for people.
The Declaration of Independence reflects John Locke's influence through the concept of unalienable rights.
The idea in the Declaration of Independence that reflects the influence of John Locke is the concept of unalienable rights, such as life, liberty, and the pursuit of happiness. Locke's philosophy emphasized these rights as inherent to individuals and not subject to infringement by governments.
which of the following can enter and exit a closed system?
a. matter and energy
b. neither energy nor matter
c. matter but not energy
d. enrgy but not matter
Answer:
The correct answer option is d. energy but not matter.
Explanation:
A system which only allows the exchange of energy to its surroundings and not the matter is known as a closed system.
An example of a closed system is when you place a lid on a saucepan. The lid does not allow the matter to enter in or leave the saucepan but it does allow the energy to transfer in the form of heat.
Therefore, energy but not matter can enter and exit a closed system.
Answer:
matter and energy
Explanation:
ANSWER FAST FOR BRAINLIEST!!
How does the force exerted by two magnets change as the magnets are moved farther apart?
The magnetic force increases.
The magnetic force decreases.
The magnetic force stays the same.
Answer:
The magnetic force decreases.- second choice
The force exerted by two magnets decreases as the magnets are moved farther apart.
Answer: B
Explanation
The magnetic force when two magnets come in contact can result in either attraction or repulsion.
The repulsion or attraction of two magnets depends on the poles in which they come into contact.
Like poles tend to repel.
Example if a magnet's south pole is brought in contact with the another magnet's south pole, the result will be both the poles will repel from each other.
Similarly, unlike poles attract.
Two billiard balls move toward each other on a table. The mass of the number three ball, m1, is 5 g with a velocity of 3 m/s. The mass of the eight ball, m2, is 6 g with a velocity of 1 m/s. After the balls collide, they bounce off each other. The number three ball moves off with a velocity of 5 m/s. What is the final velocity and direction of the eight ball? +8.6 m/s +5.7 m/s –5.7 m/s –8.6 m/s.?
Answer:
+5.7 m/s
Explanation:
According to the law of conservation of momentum is that the momentum before the collision is equal to the momentum after the collision. In an equation form it would look like this:
M₁V₁+M₂V₂ = M₁V₁'+M₂V₂'
Where:
M₁ = mass of object 1 (kg)
V₁ = velocity of object 1 before the collision (m/s)
V₁' = Final velocity of object 1 after the collision (m/s)
M₂ = mass of object 2 (kg)
V₂ = velocity of object 2 before the collision (m/s)
V₂' = Final velocity of object 2 after the collision (m/s)
According to your problem you have the following given:
M₁ = 5 g = 0.005kg
V₁ = 3 m/s
V₁' = -5m/s (It bounced off so it is going the other direction)
M₂ = 6g = 0.006kg
V₂ = -1 m/s (It is coming from the opposite direction of the 3-ball)
V₂' = ?
So we plug in what we know and solve for what we don't know.
[tex]M_1V_1+M_2V_2 = M_1V_1' + M_2V_2'\\\\(0.005kg)(3m/s)+(0.006kg)(-1m/s) = (0.005kg)(5m/s)+(0.006kg)(V_2')\\\\(0.015kg\cdot m/s)+(-0.006kg\cdot m/s)=(-0.025kg\cdot m/s)+(0.006kg)(V_2')\\\\0.009kg\cdot m/s+0.025kg\cdot m/s = (0.006kg)(V_2')\\\\\dfrac{0.034kg\cdot m/s}{0.006kg} = V_2'\\\\5.7m/s = V_2'[/tex]
Answer:
+5.7 m/s
Explanation:
Just did the assignment :)
what is the momentum of a dog of mass 20 kg that is running east with a speed of 3 m/s?
Answer:
60 kg.m/s
Explanation:
Momentum is the product of mass and velocity
p=m*v where m is mass in kg and v is velocity in m/s
Given that;
m=20kg and v=3m/s then;
p= 20×3= 60kgm/s
Answer:
60 kg * m/s east.
Explanation:
Momentum is a vector quantity, so you must include direction in the answer. Work by the guy above me ^_^
What is the angle between the incident ray and the normal ray called?
A.) The angle of refraction
B.) The angle of reflection
C.) The angle of incidence
D.) The incoming angle
Answer:
A, the angle of refraction
Answer: The angle between the incident ray and the normal ray is called as the angle of incidence.
Explanation:
For the given options:
Option A: The angle of refractionAngle of refraction is defined as the angle formed between the refracted ray and the normal ray drawn at the point of interference.
Option B: The angle of reflectionAngle of reflection is defined as the angle formed between the reflected ray and the normal ray.
Option C: The angle of incidenceAngle of incidence is defined as the angle formed between the incident ray and the normal ray.
Hence, the angle between the incident ray and the normal ray is called as the angle of incidence.
According to social exchange theory, altruistic behaviors benefit the individual who performs them.
T/F
The altruism definitely rewards the person who performs it, not immediately but in due course of time, according to the social exchange theory. Hence the given statement is TRUE.
Explanation:
Altruism is the act or behavior in which an individual performs action in regard to the concern of the other person’s happiness. It is just not implied to humans but to animals as well. It is moral principle and practice as the part of theory of social exchange which studies the social behavioral interaction.
According to social exchange theory, altruistic behaviors can indeed benefit the individual who performs them, as they may lead to indirect benefits such as the improvement of one's reputation or sense of self-worth.
Explanation:True, social exchange theory does suggest that altruistic behaviors can benefit the individual who performs them. This theory posits that all human relationships are formed by the use of a subjective cost-benefit analysis and the comparison of alternatives. In simpler terms, altruistic behaviors - those done to aid others with no obvious benefit to one's self - may still lead to indirect benefits such as the improvement of one's reputation or sense of self-worth. Therefore, it can be argued that these behaviors serve a purpose for the individuals performing them, even if the benefits are not immediate or direct.
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Try it
A volleyball player's hand applies a 39 N force while in contact with a volleyball for 2 seconds. What is the impulse
on the ball?
Answer:
The correct answer is that the impulse equals 78 N*s.
Explanation:
To solve this problem, we must first remember the meaning of impulse and its equation.
Using our knowledge that impulse = force * time, we can substitute in our given values and solve easily.
Impulse = force * time
Impulse = 39 N * 2 s
Impulse = 78 N*s
Therefore, your answer is that the impulse equals 78 N*s.
An ionic compound can conduct electricity when
A it is dissolved in water
B its crystals are ground into powder
C it is in solid form
D it is heated to just below its melting point
Answer:A it is dissolved in water
What is the change in internal energy if 20 J of heat is released from a system and the system does 50 J of work on the surroundings?
a. -70 j
b. 30 j
c. -30 j
d. 70 j
OPTION - A
Change in energy given by :-
dQ = du + dw
dQ = -20 - (-50)
dQ = -70
Luke and Carrie are driving down a straight section of the interstate at 70 mph in Luke's new convertible. Carrie is drinking a soda in the passenger seat. When she is done she tosses the bottle straight up in the air, just above the height of the car. What will happen to the bottle if air resistance is neglected?
A.
The bottle will land in Carrie's lap.
B.
Not enough information is given.
C.
The bottle will land on the interstate in front of the car.
D.
The bottle will land on the interstate behind the car.
Final answer:
The bottle will land in Carrie's lap because it maintains the same horizontal velocity as the car when tossed up, provided air resistance is ignored. The correct answer is A. The bottle will land in Carrie's lap.
Explanation:
If Carrie tosses the bottle straight up in the air above the convertible that is moving at 70 mph and air resistance is neglected, the correct answer is A. The bottle will land in Carrie's lap. This is because, according to Newton's laws, the bottle has the same horizontal velocity as the car when it is released.
Therefore, it will continue to move forward with the car at the same speed, assuming no air resistance is present to alter its path. If we were to consider air resistance, the path of the bottle could change and it might not land back in Carrie's lap.
This principle is illustrated in various physics problems, like those involving projectile motion where gravity is the only force acting on an object, and conservation of momentum in a frictionless environment.
What does every magnet possess?
A. iron metal
B.strong magnetic field
c.repulsion
D.north and south poles
Answer:
North and South poles
Explanation:
It wouldn't be a magnet if it did not have the poles, also not every magnet has a strong magnetic field, along with all above besides D
In a star, nuclear fusion occurs in the A. photosphere. B. corona. C. radiative zone. D. core.
The answer is D. core.
Answer:
yep the answer is core. (:
Explanation:
Which describes an image that can be produced by a concave lens?
The image is real and smaller than the object.
The image is virtual and larger than the object.
The image is virtual and smaller than the object.
The image is real and larger than the object.
Answer:
The image is virtual and smaller than the object.
Explanation:
A concave lens is a diverging lens, meaning that it spreads out light rays that have been refracted through it. A concave lens is thinner at its center than at its edges.
It always produces virtual images because the image appears to form on the same side of the lens where the object is placed.
The image is always smaller than the object. Far the object, smaller will be its image.
A light ray diagram of a concave lens is attached for a better understanding.
help meeee pleaseeee
Carbonation, Hydrolysis and Oxidation all relates to chemical reactions with the rocks - so these are forms of Chemical weathering
Frost wedging is where the rocks and earth is broken apart by water freezing and turning to ice. It has nothing to do with rocks themselves changing in their chemical composition. So this is a type of physical weathering.
------------------------------------------------------
Answer:
Frost wedging is a type of physical weathering.
Hydrolysis, oxidation and carbonation are all under chemical weathering
Therefore; frost wedging is a type of physical weathering
Which of the following is a measure of the amount of light a star directly emits?
A. Luminosity B. Intensity C. Wavelength D. Brightness
Luminosity is the amount of light a star directly emits from its surface.
Luminosity is a measure of the amount of light a star directly emits.
Answer : Option A
Explanation:
Light intensity is similar to brightness of the light where it is a measure of amount of light focused with respect to area and its unit is called as lux represented by lx.
Different light has different wavelengths according to the electromagnetic spectrum. Luminosity is the best option from the given ones as is a measure of amount of light emitted from an object which is here referred to a star.
Suppose an object is in free fall. Each second the object falls
a.) the same distance as in the second before
b.) a larger distance than in the second before
c.) with the same instantaneous speed
d.) with the same average speed
e.) none of the above
Answer:
The correct answer option is b) a larger distance than in the second before.
Explanation:
Supposing that an object is in free fall, each second the object would fall a larger distance than in the second before.
In Physics, free fall is the state of motion of an object where the only force acting upon it is the force of gravity.
So for a object experiencing free fall, with every passing second it covers a larger distance in comparison to the previous second.
Question 1 of 10
Multiple Choice: Please select the best answer and click "submit."
What method of forecasting predicts the arrival time of a storm based on its
current speed and other starting variables
O A. Climatology method
O B. Trends method
O C. Analog method
OD. Persistence method
Answer:
B) trends method
I'm very sure of this answer
Answer:
Trends Method
Explanation:
From
A
P
E
X
Which best explains what happens when an electron moves from an excited state to the ground state?
O
O
O
O
The electron absorbs energy as it moves to a lower energy level.
The electron absorbs energy as it moves to a higher energy level.
The electron releases energy as it moves to a higher energy level
The electron releases energy as it moves to a lower energy level.
Answer:
The electron releases energy as it moves to a lower energy level.- last choice
An "excited state" is a condition where the electron has MORE energy. The "ground state" is the lowest energy level, where the electron has the minimum possible energy.
So, when an electron moves from an excited state to the ground state, it loses energy. The electron releases energy as it moves to the lowest energy level.
(last choice)
Ryan is examining the energy of the particles in a bar of gold. What is Ryan most likely studying?
Answer:
The answer is internal energy.
Ryan is examining the internal energy of the particles in a bar of gold.
What is internal energy?The internal energy of a thermodynamic system is the energy contained within it.
It can also be defined as the total energy within the lattice of a compound. That is, the sum of the individual energy of particles of the compound.
Thus, we can conclude that Ryan is examining the internal energy of the particles in a bar of gold.
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Current enters a circuit at a:
1.positive terminal
2.negative terminal
3.low potential side
4.resistor
Which statement about covalent bonds is true
Answer:c
Explanation:
i did the usatestprep
How many feet are in a mile
Hello There!
There are 5,280 feet in 1 mile.
Have A Great Day!
The theory that light exists in quantized "chunks" was proposed in response
to which of the following?
A. Electron interference patterns
O
B. Discovery of Planck's constant
O
C. The ultraviolet catastrophe
O
D. Emission spectra
Answer: C.
Explanation:
The ultraviolet catastrophe.
Suppose the tourist in question #1 instead threw the rock with an initial velocity of 8.0
m/s (down). Determine the velocity and displacement of the rock at 4.0 s (Remember
the v; is down and must become a -8.0 m/s)
Answer:
Explanation:u=8m/s, a=8m/s*s, t=4s
Using v= u + at
v=8+-8*4
v=-24m/s
Displacement=s
Using s=½(u+v)t
s=½(8-24)4
s=½*-16*4
s=-8*4
s=32m( you can solve without observing the negative sign)
Both independent and dependent clauses
Answer: have a subject and a verb
Explanation:
Answer:
B
Explanation:
2,2,3,8,10 mean, median , range
Answer:
mean=5
median=3
range=8
Explanation:
mean- add em up and divide by the number of numbers
so 2+2+3+8+10=4+11+10+15+10=25
There are 5 numbers so 25/5=5 is the mean
median- middle (or average of middles if two middles) after data arranged from least to greatest
It already is and there is one middle so the median is 3
range=greatest minus smallest
So the range is 10-2=8.
The mean is the average so add up all the numbers and divide by the amount of numbers. This gives you 5 for the mean
The median is the middle number when they are lined up in number order. That number in this list is 3
Range is the largest number subtracted by the smallest number. 10-2=8
_____ is a property that determines how much current will flow for a given source voltage, whereas a _____ is a device that controls the current in a circuit
“RESISTANCE” is a property that determines how much current will flow for a given source voltage, whereas a “RESISTOR” is a device that controls the current in a circuit.
The property which determines the amount of current to be flown for a given source voltage is the Resistance and the device which controls it is the Resistor.
Explanation:
The resistance is the property of an electric circuit which can resist the flow of current across the circuit. Similarly, to keep in check the current of an electric circuit, resistor is used as a device, which has a predetermined or preset amount of electrical resistance. The resistance unit is ohm.