Which statement best describes the thermal properties of wool?
A. Wool is an ideal thermal insulator because it completely resists the transfer of heat.
B. Wool is an excellent thermal conductor because heat flows through it very quickly.
C. Wool lacks any useful thermal properties; it is neither a conductor nor insulator. D. Wool is an excellent thermal insulator because heat flows through it very slowly.
Wool is an excellent thermal insulator as heat transfers through it very slowly, making it ideal for clothing and blankets that keep us warm.
The best description of the thermal properties of wool is that wool is an excellent thermal insulator because heat flows through it very slowly (option B). This slow transfer of heat is due to wool's low thermal conductivity, which means it is a material that does not allow energy to pass through quickly. Unlike materials with high thermal conductivity like metals, wool keeps heat close to the body, making it ideal for use in clothing and blankets to maintain warmth.
Where are the most reactive nonmetal elements found on the periodic table?
at the top of group 17
at the bottom of group 17
at the top of group 18
at the bottom of group 18
Answer: Option (a) is the correct answer.
Explanation:
Elements of group 17 are known as halogens whereas elements of group 18 are known as noble gases.
Noble gases have completely filled valence shell. Therefore, they are stable and does not react easily.
Whereas halogens have incompletely filled sub-shells, therefore, in order to gain stability they react readily with another atom.
Halogen atoms are also electronegative in nature. On moving down the group, the electronegativity decreases. Thus, the atom at the top of group 17, that is, fluorine is the most reactive non-metal because fluorine has high electronegativity so, it readily attracts an electron in order to completely fill its sub-shell.
Thus, we can conclude that at the top of group 17 most reactive nonmetal elements are found on the periodic table.
Answer: A
Explanation: 100 on edge
What enables humans to "see" light in the infrared range of the electromagnetic spectrum? thermogram UV sensor RFID chip video camera
infrared is heat so thermogram will allow u to see it
Answer:
thermogram
Explanation:
what roles does sound play in shaping the physical world
Sound plays an important role in shaping the physical world. One of the many roles of Sound is Sound healing, it is one of the oldest forms of healing which was considered normal and used regularly and effectively. Sound can correct imbalances on every level of physical functioning and can play a positive role in the treatment of almost any medical disorder .
how does a shovel make work easier for digging a hole?
A cord of mass 0.75 kg is stretched between two supports 7.2 m apart. part a if the tension in the cord is 150 n , how long will it take a pulse to travel from one support to the other?
The time it takes for a pulse to travel from one support to the other can be calculated using the formula time = distance / speed. By using the given values of the cord's length and tension, we can calculate the speed and then find the time taken.
Explanation:To calculate the time it takes for a pulse to travel from one support to the other, we can use the formula:
time = distance / speed
Since the length of the cord is given as 7.2 m and the tension in the cord is given as 150 N, we can use these values to calculate the speed using the formula:
speed = sqrt(tension / (mass/length))
Plugging in the values, we get:
speed = sqrt(150 / (0.75/7.2)) = sqrt(150 * (7.2/0.75)) = sqrt(1440) ≈ 37.95 m/s
Now, we can calculate the time it takes for the pulse to travel the distance:
time = 7.2 m / 37.95 m/s ≈ 0.19 s
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A policeman's whistle has a _____. high pitch low amplitude low pitch
A policeman's whistle has a _____.
high pitch
What does it mean to say that science is a “systematic” process?
Science is a systematic process, which means it follows a careful method that involves observation and experimentation. Through experimentation, information is collected that supports or refutes a scientist’s hypothesis.
edginuity answer
Please help!
Explain what happens to the pitch of a cell phone ring when the wavelength of a sound wave increases.
Answer:
Pitch decreases
Explanation:
The number of oscillation or number of vibration per unit time is called the frequency of a sound wave. The frequency of sound wave is also called the pitch of the wave. It is denoted by f or [tex]\nu[/tex]. Its SI unit is hertz or Hz.
The speed of the sound wave is given by :
[tex]v=\nu\times \lambda[/tex]
It is clear form the above expression that the pitch of the sound wave is inversely proportional to the wavelength.
So, when the wavelength of a sound wave increases its pitch decreases.
The potential energy of a book on a shelf is 50 J. If the book is now on the floor (below the shelf), its potential energy is
Answer:
shelf a is increase shelf b is stay the same and shelf c is decrease
Explanation:
i did it on edu
A horse is pulling 53.0 kg plow forward while the ground exerts a 275 N force, and the plow accelerates at 0.222 m/s^2. what is the magnitude(+) of the force the ground exerts on the plow?
The police department is excited to have some new motorcycle units. One officer said that these motorcycles can go from 0 miles per hour to 80 miles per hour in just 6 seconds. The officer is describing the motorcycle's
Answer:
Explanation:
Acceleration
A 58.5-kg athlete leaps straight up into the air from a trampoline with an initial speed of 8.8 m/s. the goal of this problem is to find the maximum height she attains and her speed at half maximum height.
In order to measure motion,one needs to observe?
A.an object’s position at different times.
B.an object’s position one time.
C.an object’s size and direction.
A sealed container holding 0.0262 l of an ideal gas at 0.989 atm and 72.3 °c is placed into a refrigerator and cooled to 40.1 °c with no change in volume. calculate the final pressure of the gas.
To calculate the final pressure of a gas after cooling, the combined gas law is used. The final pressure of the gas cooled from 72.3 0C to 40.1 0C in a constant volume is calculated to be 0.896 atm.
The student is asking to calculate the final pressure of an ideal gas after it is cooled from 72.3 0C to 40.1 0C without changing its volume. To find the final pressure, you can use the combined gas law, which relates the pressure, volume, and temperature of a gas. The combined gas law is P1/T1 = P2/T2, where P1 and T1 are the initial pressure and temperature, and P2 and T2 are the final pressure and temperature. Given that the initial pressure (P1) is 0.989 atm and the initial temperature (T1) is 345.45 K (72.3 0C + 273.15), and the final temperature (T2) is 313.25 K (40.1 0C + 273.15), and the volume remains constant, we can solve for the final pressure (P2).
Initial pressure (P1): 0.989 atm
Initial temperature (T1): 345.45 K
Final temperature (T2): 313.25 K
Final pressure (P2): ?
To solve for P2, we rearrange the combined gas law to P2 = P1 imes (T2 / T1):
P2 = 0.989 atm imes (313.25 K / 345.45 K)
P2 = 0.989 atm imes 0.906 = 0.896 atm (rounded to three significant digits)
Therefore, the final pressure of the gas would be 0.896 atm after it is cooled to 40.1 0C.
When you lift an object by moving only your forearm, the main lifting muscle in your arm is the biceps. suppose the mass of a forearm is 1.40 kg . if the biceps is connected to the forearm a distance dbiceps = 2.50 cm from the elbow, how much force fbiceps must the biceps exert to hold a 1000 g ball at the end of the forearm at distance dball = 33.0 cm from the elbow, with the forearm parallel to the floor? how much force felbow must the elbow exert? draw the vectors starting from the point of application of each force. the location and orientation of the vectors will be graded. the length of the vectors will not be graded?
This problem involves understanding the concept of torque and equilibrium. It involves the calculation of the forces that the biceps and the elbow must exert to hold a ball at the end of the forearm with the forearm parallel to the floor. The force vectors are directed upwards for the biceps and elbow and downwards for the ball and forearm.
Explanation:To solve this problem, we need to use the concepts of torque and equilibrium. Forces that produce torque on the arm include the force of the biceps, the weight of the forearm, and the weight of the ball.
First, let's convert the measurements in the question into the same unit.
The mass of the ball (1000 g) in kilograms is 1 kg and the distance of the ball from the elbow (33.0 cm) in meters is 0.33 m. The mass of the forearm (1.40 kg) is already in kilograms and the distance of the bicep from the elbow (2.50 cm) in meters is 0.025 m.
Take the weight of an object as the force acting on that object which is calculated by multiplying the mass of the object by gravity (9.8 m/s²). Therefore, the weight of the ball will be 1 kg x 9.8 m/s² = 9.8 N and the weight of the forearm is 1.4 kg x 9.8 m/s² = 13.72 N.
When the forearm is in equilibrium, the clockwise torque is equal to the counter-clockwise torque. The only force exerting a clockwise torque is the biceps. Hence,
Fbiceps x biceps = Fball x ball + Fforearm x forearm
Rearranging the above equation will give us the force that the biceps must exert: Fbiceps = (Fball x ball + Fforearm x forearm) / biceps. Substitute the known values into the equation and calculate.
The elbow must exert an equal and opposite force to that of the biceps and the weights of the forearm and ball (since the forearm is in equilibrium) resulting in Felbow = Fbiceps + Fball + FForearm.
As the forces are vector quantities, the direction is important. The force vectors of the biceps and the elbow are directed upwards, while those of the ball and the forearm are directed downwards.
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A property unique to a conducting substance that determines its resistance is called
Answer:
Electrical Resistivity
Explanation:
As we know that all different type of conductors has its different unique resistivity due to which all conductors will show different resistance for same shape and size.
As we know that the resistance of a conductor is given as
[tex]R = \rho\frac{L}{A}[/tex]
here we know
[tex]\rho[/tex] = resistivity
L = length of conductor
A = crossectional area of conductor
so here for all conductors the resistivity is unique property due to which all will show different resistance
A forklift raises a 1020 N crate 3.50 m up to a shelf l. How much work is done by the forklift on the crate? The forklift does J work on the crate.
A forklift raises a 1,020 N crate 3.50 m up to a shelf. How much work is done by the forklift on the crate?
The forklift does
⇒ 3,570 J of work on the crate. the answer is 3570
Answer : Work done on the crate is 3570 J
Explanation :
Force acting on forklift due to its mass is 1020 N
Distance covered in lifting it, d = 3.5 m
Mathematically, the work done is defined as :
[tex]W=F\times d[/tex]
So, [tex]W=1020\ N\times 3.5\ m[/tex]
[tex]W=3570\ J[/tex]
The forklift does 3570 J work on the crate.
Hence, this is the required solution.
which jet stream affects weather in south Africa
The maximum kinetic energy of photoelectrons is 3.10 ev . when the wavelength of the light is increased by 50%, the maximum energy decreases to 1.50 ev . part a what is the work function of the cathode?
The work function of the cathode is found to be 0.10 eV, calculated by using the relationship between the maximum kinetic energy of photoelectrons, the photon energy, and the work function within the context of the photoelectric effect.
The question involves finding the work function of a cathode in a photoelectric effect scenario. We know that the maximum kinetic energy (KE) of photoelectrons is related to the photon energy (hf) and the work function (
W) as KE = hf - W. We were given that the kinetic energy decreased to 1.50 eV when the wavelength increased by 50%, which implies the initial wavelength corresponds to a photon energy that gives photoelectrons a kinetic energy of 3.10 eV. Let's express these energies in the equation form:
KE1 = hf1 - W, where KE1 = 3.10 eV
KE2 = hf2 - W, where KE2 = 1.50 eV and hf2 = hf1/1.5 (since the wavelength increased by 50%, energy decreases by the same factor)
By subtracting the second equation from the first, we eliminate W and can solve for hf1. Once we have hf1, we can solve for the work function using either of the equations:
3.10 eV - 1.50 eV = hf1 - hf1/1.5
1.60 eV = 0.5 * hf1
hf1 = 3.20 eV
Work function W = hf1 - KE1 = 3.20 eV - 3.10 eV = 0.10 eV
The work function of the cathode is therefore 0.10 eV.
The average mass of a rhinoceros calf is 45 kg. What is its weight in newtons? Round your answer to the nearest whole number.
A. 5N
B. 45N
C.250 N
D. 441 N
I will mark brainliest for whoever gets this right in the first 5 min
The weight of the given rhinoceros calf is equal to 441 N when its mass is 45 kg. Therefore, option (D) is correct.
What is the weight of the object?The weight of a body can be defined as the force acting on the object due to gravity. Weight can be described as a vector parameter as the gravitational force acting on the object.
The SI unit for weight is the same as that of force, which is the newton. A body with a mass of 1 Kg possesses a weight of about 9.8 N on the surface of the Earth.
The formula that can be used to calculate the weight of a body is written as follows:
W = mg
Given the mass of the rhinoceros calf, m = 45 Kg
The acceleration due to gravity on the rhinoceros calf, g = 9.8 m/s²
The weight of the rhinoceros calf on the earth will be equal to:
W = 45 Kg × 9.8 m/s²
W = 441 N
Therefore, the weight of the rhinoceros calf is 441 N.
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A fixed mass of an ideal gas is heated from 50 to 80℃ at a constant pressure of (a) 1 atm and (b) 3 atm. for which case do you think the energy required will be greater? why?
The energy required to heat a fixed mass of an ideal gas from 50 to 80℃ is the same at both 1 atm and 3 atm, as it depends on the gas's heat capacity and the temperature change, not pressure.
Explanation:The energy required to heat a fixed mass of an ideal gas from 50 to 80℃ would be the same for both cases of constant pressure at 1 atm and 3 atm. The reason behind this is that the amount of energy required to raise the temperature of an ideal gas is dependent on its heat capacity and the change in temperature, not the pressure at which it is heated. In both cases (a) and (b), the change in temperature is the same, so the energy required will also be the same.
The radius of a sphere is increasing at a rate of 4 mm/s. how fast is the volume increasing when the diameter is 40 mm?
Using r to represent the radius and t for time, you can write the first rate as:
drdt=4mms
or
r=r(t)=4t
The formula for a solid sphere's volume is:
V=V(r)=43πr3
When you take the derivative of both sides with respect to time...
dVdt=43π(3r2)(drdt)
...remember the Chain Rule for implicit differentiation. The general format for this is:
dV(r)dt=dV(r)dr(t)⋅dr(t)dt with V=V(r) and r=r(t) .So, when you take the derivative of the volume, it is with respect to its variable r (dV(r)dr(t)) , but we want to do it with respect to t (dV(r)dt) . Since r=r(t) and r(t) is implicitly a function of t , to make the equality work, you have to multiply by the derivative of the function r(t) with respect to t (dr(t)dt) as well. That way, you're taking a derivative along a chain of functions, so to speak (V→r→t ).
Now what you can do is simply plug in what r is (note you were given diameter) and what drdt is, because dVdt describes the rate of change of the volume over time, of a sphere.
dVdt=43π(3(20mm)2)(4mms) =6400πmm3sSince time just increases, and the radius increases as a function of time, and the volume increases as a function of a constant times the radius cubed, the volume increases faster than the radius increases, so we can't just say the two rates are the same.
The volume of the sphere is increasing at a rate of approximately 0.005m³/s when the diameter is 40 mm.
Explanation:To find the rate at which the volume of the sphere is increasing, we need to use the formula for the volume of a sphere, which is V = (4/3)πr³. Given that the radius is increasing at a rate of 4 mm/s, we can substitute the value of the radius and its rate of change into the formula to find the rate of change of the volume.
When the diameter is 40 mm, the radius is half of that, which is 20 mm. Converting the radius to meters, we get r = 0.02 m. Now we differentiate the volume formula with respect to time to get dV/dt = 4π(0.02)²(0.04) = 0.0016π m³/s or approximately 0.005m³/s.
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A spring with a spring constant of 95 n/m is compressed a distance of 0.45 m from its relaxed position. by how much does the spring\'s potential energy change?
The potential energy change of a spring with a spring constant of 95 N/m compressed by 0.45 m is approximately 9.62 J, calculated using the formula U = 1/2 kx².
Explanation:When a spring with a spring constant of 95 N/m is compressed a distance of 0.45 m from its relaxed position, the potential energy of the spring changes according to the formula for elastic potential energy, U = 1/2 kx², where 'k' is the spring constant and 'x' is the distance of compression or extension from the equilibrium position. In this case, the spring's potential energy change is calculated as U = 1/2 × 95 N/m × (0.45 m)².
By computing this, U = 1/2 × 95 × 0.45² = 0.5 × 95 × 0.2025 J. This results in U = 9.61875 J, so the potential energy of the spring changes by approximately 9.62 J.
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the lowest-pitched sounds humans can generally hear have a frequency of roughly 20 Hz. What is the approximate wavelength of these sound waves if their wave speed is 340 m/s?
Final answer:
The wavelength of the lowest-pitched sounds (20 Hz) humans can generally hear, with a wave speed of 340 m/s, is calculated using the formula λ = v / f, which yields a wavelength of approximately 17 meters.
Explanation:
To calculate the wavelength of the lowest-pitched sounds humans can generally hear, we use the basic formula that relates the speed of a wave (v) to its frequency (f) and wavelength (λ):
v = f λ
Given that the frequency (f) is 20 Hz and the wave speed (v) is 340 m/s, we can rearrange the formula to solve for wavelength (λ).
λ = v / f
Plug in the known values:
λ = 340 m/s / 20 Hz
λ = 17 meters
The wavelength for a sound with a frequency of 20 Hz, traveling at a speed of 340 m/s, is therefore approximately 17 meters.
If electrons of energy 12.8 ev are incident on a gas of hydrogen atoms in their ground state, photons can be emitted by the excited gas. how many different photon energies could you possibly observe?
Electrons with 12.8 eV energy can excite hydrogen atoms to several higher energy levels without ionizing them. Upon de-excitation, these atoms can emit a series of photons, each with a unique energy corresponding to the energy differences between these levels. Therefore, a variety of different photon energies could be observed, each corresponding to specific transitions between the energy levels.
When electrons of energy 12.8 eV are incident on hydrogen atoms in their ground state, the electrons can be excited to higher energy levels. To determine how many different photon energies can be observed, we must consider the energy levels that 12.8 eV can reach from the ground state. The ground state of hydrogen is -13.6 eV. An electron in this state can be excited to energy levels such as -3.4 eV (second energy level), -1.51 eV (third energy level), and -0.85 eV (fourth energy level), and so on, as long as the energy is less than 12.8 eV. However, an important point to note is that the energy required to excite an electron must match the energy difference between these levels precisely. Upon returning to the ground state or another lower energy state, these electrons will emit photons with energies corresponding to the differences in energies between these levels.
Which ball (if either) has the greatest speed at the moment of impact
Whichever ball is placed higher has the greatest speed at the moment of impact. Speed may be described as the distance an item goes in the amount of time.
What is speed?The distance that an item travels in relation to the length of time it takes to do so may be used to define speed. In other terms, it is a determination of an object's motion's speed without direction Velocities are what we get when speed and direction are combined.
Speed may be described as the distance an item goes in the amount of time it needs to do so. To put it in another way, it is an estimate of how swiftly something travels. Speed is measured in metres per second, or m/s, since the distance is measured in meters and the time is measured in seconds. Whichever ball is placed higher has the greatest speed at the moment of impact.
Therefore, whichever ball is placed higher has the greatest speed at the moment of impact.
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A 2.03 kg book is placed on a flat desk. suppose the coefficient of static friction between the book and the desk is 0.522 and the coefficient of kinetic friction is 0.283. how much force is needed to begin moving the book?
A 2.03 kg book is placed on a flat desk, with a coefficient of static friction between the book and the desk of 0.522 and a coefficient of kinetic friction of 0.283, requires a force of 10.4 N to start moving.
First, we have to calculate the Normal force (N), which, in a flat horizontal desk, has the same magnitude and opposite sense as the weight of the object (W). We can calculate its magnitude using the following expression.
[tex]|N| = |W| = m \times g = 2.03 kg \times \frac{9.81m}{s^{2} } = 19.9 N[/tex]
where,
m: mass of the objectg: Earth's gravityTo begin moving the book, we must overcome the highest static friction force (F), which can be calculated using the following expression.
[tex]F = \mu \times N = 0.522 \times 19.9 N = 10.4 N[/tex]
where,
μ: coefficient of static frictionA 2.03 kg book is placed on a flat desk, with a coefficient of static friction between the book and the desk of 0.522 and a coefficient of kinetic friction of 0.283, requires a force of 10.4 N to start moving.
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KCl(aq) + AgF(aq) → AgCl(s) + KF(aq) If 0.45 moles of potassium chloride are consumed completely and we start with twice as much silver fluoride, how many moles of solid silver chloride will be produced?
Answer
0.45 moles of silver chloride will be produced
Explanation
The mole ratios for the reactions are 1 for all reactants and reactants. This means that 1 mol of potassium chloride will react with 1 mol of silver fluoride to produce 1 mol of silver chloride and 1 mol of potassium fluoride.
If only 0.45 mol of potassium chloride is available to react with 0.9 mol of silver fluoride, the potassium chloride will be the limiting reagent in this reaction. This means that only 0.45 mol of each of the product will be formed. This means that only 0.45 mol of silver chloride will be formed.
.
The value for the index of refraction for any material must be