You pour 170 g hot coffee at 78.7°c and some cold cream at 7.50°c to a 115-g cup that is initially at a temperature of 22.0°c. the cup, coffee, and cream reach an equilibrium temperature of 58.0°c. the material of the cup has a specific heat of 1091 j/(kg · k) and the specific heat of both the coffee and cream is 4190 j/(kg · k). assume that no heat is lost to the surroundings or gained from the surroundings. (a) does the cream lose heat or gain heat?
The cream will gain heat when added to the hot coffee until they reach an equilibrium temperature. Practice problems cover several aspects of heat transfer and thermodynamics, including evaporation and specific heat calculations.
Explanation:The cream will gain heat when it is mixed with the hot coffee and they reach an equilibrium temperature. Overall, when two substances at different temperatures are mixed without any heat loss to the surroundings, the warmer substance will lose heat and the cooler substance will gain heat until they come to the same temperature.
In the provided scenario, the hot coffee initially at 78.7°C will lose heat, while the cold cream at 7.50°C will gain heat. This occurs because heat flows from the warmer object to the cooler one until thermodynamic equilibrium is achieved at 58.0°C.
Several practice problems related to heat transfer and thermodynamics were mentioned. Problems include finding the amount of coffee that must evaporate to cool it down, calculating final temperatures of mixtures, and understanding specific and latent heats.
A metal ball with diameter of a half a centimeter and hanging from an insulating thread is charged up with 1010 excess electrons. an initially uncharged identical metal ball hanging from an insulating thread is brought in contact with the first ball, then moved away, and they hang so that the distance between their centers is 20 cm. (a) calculate the electric force one ball exerts on the other, and state whether it is attractive or repulsive. (enter the magnitude of the force.)
Using Coulomb's law, the electric force between the two charged metal balls, each with 505 excess electrons after contact, and separated by 20 cm, is found to be 1.454 x 10^-24 N. The force is repulsive because the charges on the metal balls are both negative.
Explanation:To calculate the electric force one charged metal ball exerts on another, we need to use Coulomb's law, which is given by:
F = k |q1 * q2| / r^2
Where:
F is the electric force between the charges,k is Coulomb's constant (8.988 x 10^9 N m^2/C^2),q1 and q2 are the magnitudes of the charges,r is the distance between the centers of the two charges.When the two metal balls are brought into contact, the 1010 excess electrons will distribute evenly between both balls, meaning each ball will end up with 505 excess electrons. The charge of one electron is approximately -1.602 x 10^-19 C. Therefore, the charge on each ball after contact is 505 * -1.602 x 10^-19 C = -8.081 x 10^-17 C.
Because both balls hold negative charges, the force between them will be repulsive. The distance r is given as 20 cm, which is 0.2 meters. Thus, we can calculate the electric force:
F = (8.988 x 10^9 N m^2/C^2)*((-8.081 x 10^-17 C)^2) / (0.2 m)^2
After performing the calculation, the magnitude of the electric force between the balls is found to be:
F = 1.454 x 10^-24 N
This electric force is extremely small and generally would not be noticeable under normal circumstances.
What is an example of a negative incentive for producers
An example of a negative incentive for producers is the sharp increase in production costs. Producers are the one who manage the production costs and even the production budget. Anything that relates the production department is entitled to the management of production producers.
There is what we called positive and negative incentives and both of these can affect consumers and producers. Positive incentives are those situations which will give a certain outcome that will benefit the producers, for example, during the peak season there will be a high demand of products, and this gives the chance of producers to demand a higher price from the consumers, in this situation, there will be a big chance of increase sales. A sharp increase in production costs is a loss for the producers. If there will be an increase in production costs, the budget will be greatly affective and even though it is not a peak season, there’s a big chance also to increase prices which we know, consumers are not fond of.
A coffee company wants to make sure that their coffee is being served at the right temperature. if it is too hot, the customers could burn themselves. if it is too cold, the customers will be unsatisfied. the company has determined that they want the average coffee temperature to be 65 degrees
c. what is the parameter?
Answer:
Average temperature of the cup of coffee.
Explanation:
If for a sample of population it’s related with statistics.
But in a parameter the whole population should be considered in a survey.
When the all customers in consideration of this survey it’s considered as a parameter.
Further explanation:
Parameters are numbers which are summarize data for an entire population. But statistics are used to summarize data by using a sample.
An unknown population average is known as a parameter. A known sample average is known as a statistic. Here the survey has done with all the customers come to the shop daily. This is considered to be a parameter. If it is a statistic they should select a specific sample of customers.
But since all the customers comes to the shop has been considered in the survey this is a parameter of average temperature of sup of coffee consume by customers.
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1. statistic https://brainly.com/question/12999800 (answer by ardni313)
Keywords:
Average temperature, statistic, samples and parameter
The parameter defines the statistical attributes or measures which is derived from a population. Since the average measure of temperature of coffee is derived from a total population, it is a parameter.
Statistics are statistical measures such as average, median or other values which are derived from the sample. The average coffee temperature is a measure derived from the population of the coffee being served.Therefore, the average temperature of value of the coffee is derived from the population. Hence, it is the Parameter.
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a body of mass 1 kg is placed at a distance of 2 m from another body of mass 10 kg. At what distance from the body of mass 1 kg, another body must be placed so that the net gravitational force acting on the body of mass 1 kg is zero
To answer this problem, we will use the formula for gravitational force:
F = G m1 m2 / r^2
Where,
G = gravitational constant (6.67 * 10^-11)
m = mass of a body
r = distance between two bodies
To have a net gravitational force equal to zero acting on body of mass 1 kg, then the forces of 1 kg and 10 kg bodies and 1 kg and 5 kg bodies should be equal.
F1 (1 kg and 10 kg) = F2 (1 kg and 5 kg)
Therefore,
(1 kg) (10 kg) / (2 m)^2 = (1 kg) (5 kg) / r2^2
Calculating for r2 (distance of another body 5 kg from body of mass 1 kg):
r2^2 = 2
r2 = 1.41 m (ANSWER)
Therefore another body of mass 5 kg should be placed 1.41 m from body of mass 1 kg to have a net gravitational force equal to zero.
What is the maximum capacity of an analog circuit with a bandwidth of 4000 hz using qam?
How strong is the electric field between the plates of a 0.86 µf air-gap capacitor if they are 2.0 mm apart and each has a charge of 64 µc?
Here we will look at a more complex problem for which we will use all three of our primary constant acceleration equations. a motorcyclist heading east through a small iowa town accelerates after he passes a signpost at x=0 marking the city limits. his acceleration is constant: ax=4.0m/s2. at time t=0, he is 5.0 m east of the signpost and has a velocity of v0x=15m/s. (a) find his position and velocity at time t=2.0s. (b) where is the motorcyclist when his velocity is 25 m/s?
A circuit contains a 6.0-v battery, a 4.0-w resistor, a 0.60-µf capacitor, an ammeter, and a switch all in series. what will be the current reading immediately after the switch is closed?
Answer:
I = 0.667 A
Explanation:
A capacitor behaves like a short circuit at t = 0 immediately after the switch is closed, therefore we can discard it from the equation, the resistance is given in watts or power units equivalent to current by voltage and the ammeter behave like a short circuit by nature.
Considering all of the above, the circuit looks like a battery in series with a resistor, therefore, we can use the power equation to solve the problem as follow:
P = I*V
4W = I*6V
I = 0.667 A
A cylindrical cable of radius 8.57 mm carries a current of 25.5 a, uniformly spread over its cross-sectional area. at what distance from the center of the wire is there a point within the wire where the magnetic field is 0.447 mt?
A car braked with a constant deceleration of 8 ft/s2, producing skid marks measuring 100 ft before coming to a stop. how fast was the car traveling when the brakes were first applied?
To find the initial speed of the car when the brakes were first applied, you can use the formula: v^2 = u^2 + 2as. Plugging in the given values, we find that the car was traveling at approximately 28.3 ft/s (or 19.3 mph) when the brakes were first applied.
Explanation:To find the initial speed of the car when the brakes were first applied, you can use the formula:
v^2 = u^2 + 2as
v is the final velocity, which is 0 ft/s since the car comes to a stopu is the initial velocity, which we need to finda is the deceleration, which is given as 8 ft/s^2s is the distance, which is given as 100 ftPlugging in the values into the formula, we get:
0 = u^2 + 2(8)(100)
Solving for u, we find that the car was traveling at approximately 28.3 ft/s (or 19.3 mph) when the brakes were first applied.
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The rear window of a van is coated with a layer of ice at 0°c. the density of ice is 917 kg/m3, and the latent heat of fusion of water is 3.35 x 105 j/kg. the driver of the van turns on the rear-window defroster, which operates at 12 v and 23
a. the defroster directly heats an area of 0.65 m2 of the rear window. what is the maximum thickness of ice above this area that the defroster can melt in 4.3 minutes?
The Hubble Space Telescope (HST) orbits 569,000m above Earth’s surface. Given that Earth’s mass is 5.97 × 10^24 kg and its radius is 6.38 × 10^6 m, what is HST’s tangential speed?
Determine how long it will take an object to rotate through 10.0 revolutions at an angular velocity of 4.8 radians per second. use . round the answer to the nearest tenth.
A post office has a single line for customers waiting for the next available postal clerk. there are two postal clerks who work at the same rate. the arrival rate of customers follows a poisson distribution, while the service time follows an exponential distribution. the average arrival rate is three per minute and the average service rate is two per minute for each of the two clerks. what is the average length of the line? 3.429 1.929 1.143 0.643 none of these
What is the potential difference vab between points a and b when the switch s is open?
The potential difference vab between points a and b when the switch s is open can be calculated using the formula VAB = Ed where E is the electric field intensity and d is the distance between the points.
Explanation:The potential difference vab between points a and b when the switch s is open can be calculated using the formula VAB = Ed, where E is the electric field intensity and d is the distance between the points. The potential difference is measured in volts (V).
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The surface or material that underlies a two-dimensional work of art is called the ____.
The term for the surface or material that underlies a two-dimensional work of art is 'substrate'. It plays a critical role in the final appearance of the artwork, and its understanding is key to appreciating a given piece of art.
Explanation:The surface or material that underlies a two-dimensional work of art is called the substrate. This term refers to the material on which the artwork is created. For example, in a painting, the substrate could be the canvas. Similarly, for a drawing, the substrate might be a piece of paper. The substrate plays a vital role in the final appearance of the artwork.
One can relate the concept of substrate in art to Aristotle's explanation of substance as a composite of matter and form. In his perspective, the form is the unchanging purpose or idea informing each particular instance, while the substrate (in his terminology, matter or material cause) contributes to the physical properties of the artwork. Therefore, understanding the substrate is an essential aspect of appreciating a given piece of art.
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A thin film of polystyrene is used as an antireflective coating for fabulite (known as the substrate). the index of refraction of the polystyrene is 1.49, and the index of refraction of the fabulite is 2.409. what is the minimum thickness of film required? assume that the wavelength of the light in air is 500 nanometers.
To
solve this problem, we assume that the wavelength of the light in air is 500
nanometers.
For this case we only need the refractive index of the polystyrene. For an antireflective coating, we need a quarter of wave thickness at the wavelength in the air. Which means that the antireflective coating needs to be as thick as 1/4 of the wavelength, divided by the coating’s refractive index. This is expressed mathematically in the form:
x = λ / (4 * n)
where,
x = thickness
λ = wavelength of light
n = index of refraction of polystyrene
Substituting:
x = 500 nm / (4
* 1.49)
x = 500 nm / 5.96
x = 83.90 nm
The minimum thickness of the film required assuming that the wavelength of the light in air is 500 nanometers is; 83.9 nm
Calculations about Destructive Interference
We are given;
Index of refraction of polystyrene; η_p = 1.49
Index of refraction of Fabulite; η_f = 2.409
Wavelength of the light in air; λ = 500 nm
In this question, it will be discovered that light will first of all be reflected two times, first from the upper layer of coating and then from the interface between the coating and the polystyrene material.
The additional path travelled by the light in coating is 2t while the path difference is 2tη_p.
Thus, minimum thickness of film required will be gotten from the formula used in destructive interference which is;
2tη_p = λ/2
t = λ/2 * 1/2η_p
t = λ/(4η_p)
t = 500/(4 * 1.49)
t = 83.9 nm
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A(n) _________ is responsible for collecting light rays previously focused on the specimen.
Answer:
Objectives lens are responsibleMaria works in a hardware store. A bin of aluminum nails and a bin of iron nails are knocked over, and the nails get mixed up. Both sets of nails are the same color and size.
What makes separating the nails a fairly easy job?
A. Aluminum is heavier and iron is lighter.
B. Iron settles in water, while aluminum floats.
C. Aluminum is magnetic, and iron is non-magnetic.
D. Iron is magnetic, and aluminum is non-magnetic.
The correct answer is D. Iron is magnetic, and aluminum is non-magnetic.
Explanation:
Aluminum and iron are both metals; additionally, these materials are similar in color. However, because they are different elements they have different properties, this includes their weight as iron is heavier than aluminum; their melting point as iron has a higher melting point and their magnetic properties. Indeed while the iron is magnetic aluminum is non-magnetic, this means, aluminum does not stick to magnets. According to this, Maria could separate aluminum and iron nails using a magnet, this is fairly an easy job because iron is magnetic, and aluminum is non-magnetic.
A standing wave is set up in a 200-cm string fixed at both ends. the string vibrates in 5 distinct segments when driven by a 120-hz source. what is the wavelength?
The wavelength of a standing wave is equivalent to:
wavelength = 2 l / n
Where l is the length of
the string and n is the number of segments.
so, wavelength = 2 (0.2 m) / 5
wavelength = 0.08m (ANSWER)
Answer:
[tex]\lambda=80\ cm[/tex]
Explanation:
It is given that,
Length of the string, L = 200 cm = 2 m
Frequency, f = 120 Hz
It vibrates in 5 distinct segments such that there is fifth harmonics. For a string fixed at both ends, the wavelength is given by :
[tex]\lambda=\dfrac{2}{5}L[/tex]
[tex]\lambda=\dfrac{2}{5}\times 2[/tex]
[tex]\lambda=0.8\ m[/tex]
[tex]\lambda=80\ cm[/tex]
So, the wavelength of the string fixed at both ends is 80 cm. Hence, this is the required solution.
The ______ of a vector is always a positive quantity.
The magnitude of a vector, representing its 'length' or 'size', is always a positive quantity. It's graphically depicted as the length of an arrow representing the vector, and calculated as the square root of the sum of the squares of the vector components.
Explanation:The __magnitude__ of a vector is always a positive quantity. In mathematics and physics, a vector is a quantity described by both magnitude and direction. The magnitude of a vector refers to its 'length' or 'size', irrespective of its direction. It is expressed as a positive scalar quantity.
When a vector is depicted graphically, it's represented by an arrow. The length of the arrow is proportional to the vector's magnitude, meaning the longer the arrow, the greater the magnitude.
Magnitude is calculated as the square root of the sum of the squares of the vector's components. For instance, for a vector A in two-dimension with components Ax and Ay, its magnitude A is calculated by the equation: A = sqrt(Ax^2 + Ay^2). No matter what the direction is, the resulting magnitude will always be a positive scalar.
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The time a basketball player spends in the air when shooting a basket is called the "hang time." the vertical leap l measured in feet is related to the hang time t measured in seconds by the equation lequals=4t2. suppose that a basketball player has a vertical leap of 4 feet 4 inches. find the hang time for this leap.
I believe that L is in feet while t is in seconds. To find for the hang time, all we have to do is to plug in the value of L in feet in the equation.
4 inches is equivalent to 4/12 feet or 0.33 feet, therefore the total L is:
L = 4.33 ft
Using the equation to find for t:
L = 4 t^2
4.33 = 4 t^2
t = 1.04 s
To calculate the hang time for a basketball player with a vertical leap of 4 feet 4 inches, solve the equation l = 4[tex]t^2[/tex] to find that the hang time is approximately 1.041 seconds.
The vertical leap l is related to the hang time t by the equation l = 4[tex]t^2[/tex]. To find the hang time for a basketball player with a vertical leap of 4 feet 4 inches (which is 4.333 feet), we plug this value into the equation and solve for t:
4.333 = 4[tex]t^2[/tex]
[tex]t^2[/tex] = 4.333 / 4
[tex]t^2[/tex] = 1.08325
t = [tex]\sqrt{(1.08325)[/tex]
t ≈ 1.041
Hence, the hang time for this leap is approximately 1.041 seconds.
How are chemical reactions classified?
The types of chemical reactions are
a) Combination reaction.
b) Decomposition reaction.
c) Displacement reaction.
d) Double Displacement reaction.
e) Precipitation Reaction.
What are chemical reactions?In a chemical reaction, one or more chemicals , also known as reactants are changed into one or more other substances, known as products. In a chemical reaction, the atoms that make up the reactants are rearranged to produce various products.
Chemical equations, which depict the reactants and products of the reaction using chemical symbols and chemical formulae, can be used to represent chemical reactions. The relative numbers of atoms or molecules participating in the reaction are indicated by the coefficients placed in front of the chemical formulae.
Given data ,
The types of chemical reactions are given as
Combination reaction, Decomposition reaction , Displacement reaction , Double Displacement reaction , Precipitation Reaction
And , the characteristics of a chemical reaction are evolution of gas , formation of a precipitate , change in color or temperature and state , formation of new substances
Thermodynamic and kinetic characteristics govern the many types of chemical processes, and they may be modeled by a number of factors including energy, entropy, and Gibbs free energy change.
Hence , the types of chemical reactions are solved
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Give three examples from your life of magnetic force.
Initially the clean air act of 1990 required ___ of the nationâs dirtiest coal burning plants to cut down on emissions
a.50
b.71
c.111
d.2300
By what amount does the sound intensity decrease when the distance to the source doubles?
The relationship of the two is that, the sound intensity is inversely proportional to the square of the distance of the source.
I α 1 / r^2
Where I = intensity and r = distance from source
From this, we can equate two conditions 1 and 2:
I1 / I2 = r2^2 / r1^2
So when r2 = 2 r1, the intensity becomes:
I1 / I2 = (2r1 / r1)^2
I1 / I2 = 4
I2 = I1 / 4
So when we double the distance of the source, the intensity of the sound reduces by a factor of 4 (divided by 4).
What is the weight of a 100-kg
the moon (gravity on the moon is 1.62m/s)
A man whose weight is 650 N is standing on the ground. The force the ground exerts on him is _____.
The force the ground exerts on him is 650 N.
What is force?The push or pull on an object with mass that causes it to change its velocity.
According to law of newton
"Every action has an equal and opposite reaction."
This means that the ground is exerting the same amount of force as the man, 650 N.
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When studying whiplash resulting from rear end collisions, the rotation of the head is of primary interest. an impact test was performed, and it was found that the angular acceleration of the head is defined by the relation α = 700cosθ + 70sinθ, where α is expressed in rad/s2 and θ in radians. knowing that the head is initially at rest, determine the angular velocity of the head when θ = 30°?
The correct answer is[tex]\(\boxed{\omega \approx 479.0 \text{ rad/s}}\)[/tex].
To determine the angular velocity of the head when[tex]\(\theta = 30^\circ\),[/tex] we need to integrate the angular acceleration with respect to time. However, since angular acceleration is given as a function of [tex]\(\theta\)[/tex], we will use the relationship between angular acceleration [tex](\(\alpha\))[/tex], angular velocity[tex](\(\omega\))[/tex], and angle [tex](\(\theta\))[/tex] to find the angular velocity as a function of [tex]\(\theta\).[/tex]
The relationship between angular acceleration, angular velocity, and angle is given by:
[tex]\[\alpha = \frac{d\omega}{dt} = \frac{d\omega}{d\theta} \cdot \frac{d\theta}{dt} = \omega \frac{d\omega}{d\theta}\][/tex]
Since[tex]\(\alpha\)[/tex]is a function of [tex]\(\theta\)[/tex], we can write:
[tex]\[\omega \frac{d\omega}{d\theta} = 700\cos\theta + 70\sin\theta\][/tex]
To find [tex]\(\omega\),[/tex] we separate variables and integrate:
[tex]\[\int \omega \, d\omega = \int (700\cos\theta + 70\sin\theta) \, d\theta\][/tex]
Integrating both sides, we get:
[tex]\[\frac{\omega^2}{2} = 700\sin\theta - 70\cos\theta + C\][/tex]
where [tex]\(C\)[/tex] is the constant of integration. To find [tex]\(C\)[/tex], we use the initial condition that the head is initially at rest, which means[tex]\(\omega = 0\)[/tex] when [tex]\(\theta = 0\)[/tex]. Plugging these values into the equation, we find:[tex]\[0 = 700\sin(0) - 70\cos(0) + C\]\[C = 70\][/tex]
Now we have the constant[tex]\(C\)[/tex], and we can find the angular velocity when [tex]\(\theta = \frac{\pi}{6}\) radians (or \(30^\circ\)):[/tex][tex]\[\frac{\omega^2}{2} = 700\sin\left(\frac{\pi}{6}\right) - 70\cos\left(\frac{\pi}{6}\right) + 70\] \[\frac{\omega^2}{2} = 700\left(\frac{1}{2}\right) - 70\left(\frac{\sqrt{3}}{2}\right) + 70\] \[\frac{\omega^2}{2} = 350 - 35\sqrt{3} + 70\] \[\frac{\omega^2}{2} = 420 - 35\sqrt{3}\][/tex]
Multiplying both sides by 2 to solve for[tex]\(\omega^2\)[/tex]:
[tex]\[\omega^2 = 2(420 - 35\sqrt{3})\]\[\omega^2 = 840 - 70\sqrt{3}\][/tex]
Taking the square root of both sides to find [tex]\(\omega\)[/tex]:
[tex]\[\omega = \sqrt{840 - 70\sqrt{3}}\][/tex]
Now we can calculate the numerical value:
[tex]\[\omega \approx \sqrt{840 - 70 \times 1.732}\] \[\omega \approx \sqrt{840 - 121.24}\] \[\omega \approx \sqrt{718.76}\] \[\omega \approx 479.0 \text{ rad/s}\][/tex]
Therefore, the angular velocity of the head[tex]when \(\theta = 30^\circ\) is approximately \(\boxed{479.0 \text{ rad/s}}\)[/tex]