Answer:
The most important is that the thermal conductivity of the armadillas several orders of magnitude lower than the thermal conductivity of the metal, therefore it is easier to maintain the temperature in winter
Explanation:
Cement and bricks are used in the construction of houses instead of metal, for several reasons
* The most important is that the thermal conductivity of the armadillas several orders of magnitude lower than the thermal conductivity of the metal, therefore it is easier to maintain the temperature in winter
* Metal has more oxidation problems than brick
* The cost of sheet metal is higher than the cost of cement brick.
(a) If two sound waves, one in a gas medium and one in a liquid medium, are equal in intensity, what is the ratio of the pressure amplitude of the wave in the liquid to that of the wave in the gas? Assume that the density of the gas is 2.27 kg/m3 and the density of the liquid is 972 kg/m3. The speed of sound is 376 m/s in the gas medium and 1640 m/s in the liquid. (b) If the pressure amplitudes are equal instead, what is the ratio of the intensities of the waves (of the one in the liquid to that in the gas)?
Answer:
(a) The ratio of the pressure amplitude of the waves is 43.21
(b) The ratio of the intensities of the waves is 0.000535
Explanation:
Given;
density of gas, [tex]\rho _g[/tex] = 2.27 kg/m³
density of liquid, [tex]\rho _l[/tex] = 972 kg/m³
speed of sound in gas, [tex]C_g[/tex] = 376 m/s
speed of sound in liquid, [tex]C_l[/tex] = 1640 m/s
The of the sound wave is given by;
[tex]I = \frac{P_o^2}{2 \rho C} \\\\P_o^2 = 2 \rho C I\\\\p_o = \sqrt{2 \rho CI}[/tex]
Where;
[tex]P_o[/tex] is the pressure amplitude
[tex]P_o_g= \sqrt{2 \rho _g C_gI} -------(1)\\\\P_o_l= \sqrt{2 \rho _l C_lI}---------(2)\\\\\frac{P_o_l}{P_o_g} = \frac{\sqrt{2 \rho _l C_lI}}{\sqrt{2 \rho _g C_gI}} \\\\\frac{P_o_l}{P_o_g} = \sqrt{\frac{2 \rho _l C_lI}{2 \rho _g C_gI} }\\\\ \frac{P_o_l}{P_o_g} = \sqrt{\frac{ \rho _l C_l}{ \rho _g C_g} }\\\\ \frac{P_o_l}{P_o_g} = \sqrt{\frac{ (972)( 1640)}{ (2.27)( 376)} }\\\\\frac{P_o_l}{P_o_g} = 43.21[/tex]
(b) when the pressure amplitudes are equal, the ratio of the intensities is given as;
[tex]I = \frac{P_o^2}{2 \rho C}\\\\I_g = \frac{P_o^2}{2 \rho _g C_g}-------(1)\\\\I_l = \frac{P_o^2}{2 \rho _l C_l}-------(2)\\\\\frac{I_l}{I_g} = (\frac{P_o^2}{2 \rho _l C_l})*(\frac{2\rho_gC_g}{P_o^2} )\\\\\frac{I_l}{I_g} = \frac{\rho _gC_g}{\rho_lC_l} \\\\\frac{I_l}{I_g} = \frac{(2.27)(376)}{(972)(1640)}\\\\ \frac{I_l}{I_g} = 0.000535[/tex]
Which statement best compares the accelerations of two objects in free fall?
O The heavier object has a greater acceleration.
O The object that has the greater surface area has the lower acceleration.
O The object that has the smaller mass has the greater acceleration.
O The objects have the same acceleration,
Answer:
D) The objects have the same acceleration. With no air resistance and the same gravity, the acceleration due to gravity should be the same for both objects.
Answer:
b
Explanation:
Superman is riding his bicycle. At the base of a hill, he has a specific amount of kinetic energy. Then he coasts up the hill without pedaling. He comes to a stop at the top of the hill. Why is Superman’s potential energy at the top of the hill less than his kinetic energy at the bottom of the hill?
A. The hill did work on the bicycle as he went up the hill.
B. The rest of the energy is stored in the muscles of his body.
C. He still has kinetic energy while stopped on the top of the hill.
D. Friction and air resistance created heat on his trip up the hill.
Answer:
D. Friction and air resistance created heat on his trip up the hill.
Explanation:
Energy transformation from one form to another is not 100% efficient. This is the postulate of the first law of thermodynamics.
Most of the energy transformation is not purely 100%.
When energy is transformed, some are usually wasted.
In this case, in moving from bottom up, Superman produced some heat and encountered air resistance. To reach the top, he must have overcome the resistance and produce enough heat to power him through. This reduces the amount of potential energy that should have been the same as the kinetic energy down below.Oil is a powerful source of energy used for cars, machines, and many other purposes. While studying sources of energy that could replace the use of oil, a student thinks about solar power, wind power, nuclear power, and electric batteries. The students asks, "Which type of source will waste the least energy and provide the most energy in all situations?" Which best describes why a scientist would ask a different question than this one? The question asks about subjective personal preferences regarding energy. The question focuses on the objective measurements of amounts of energy. The question has too wide of a focus, as though all situations can be studied at once. The question is focused on the future and finding new answers about changing needs.
Answer:
The question has too wide of a focus, as though all situations can be studied at once.
Explanation:
A freight train consists of two 8.00 \times 10^5~\text{kg}8.00×10 5 kg engines and 45 cars with average masses of 5.50 \times 10^5~\text{kg}5.50×10 5 kg. What force must each engine exert backward on the track to accelerate the train at a rate of 5.00 \times 10^{-2}~\text{m/s}^25.00×10 −2 m/s 2 if the force of friction is 7.50 \times 10^5 ~\text{N}7.50×10 5 N, assuming the engines exert identical forces? This is not a large frictional force for such a massive system. Rolling friction for trains is small, and consequently trains are very energy-efficient transportation systems.
Answer:
F₁ = 4.29 x 10⁵ N
Explanation:
The total force required to move the freight train with the given acceleration is given by the following formula:
F = ma + f
where,
F = Total Force Required from both engines = ?
m = equivalent mass of system = 2(8 x 10⁵ kg) + 5.5 x 10⁵ kg = 21.5 x 10⁵ kg
a = required acceleration = 5 x 10⁻² m/s²
f = force of friction = 7.5 x 10⁵ N
Therefore,
F = (21.5 x 10⁵ kg)(0.05 m/s²) + 7.5 x 10⁵ N
F = 8.575 x 10⁵ N
Now, for identical forces in each engine can be given as:
Force exerted by each engine = F₁ = F/2
F₁ = 8.575 x 10⁵ N/2
F₁ = 4.29 x 10⁵ N
An object is thrown vertically upward at 35 m/s. Taking g=10 m/s2, the velocity of the object 5 s later is?
Given :
Initial Velocity (u) = 35 m/s.Time taken (t) = 5 secondsgravitation (g) = 10 m/s²Final Velocity (u) = ?Answer:
↪ v = u + gt
↪ v = 35 - 10 × 5
↪ v = 35 - 50
↪ v = -15 m/s
Therefore,the Velocity of the object 5 seconds later is -15 m/s.
a dump truck slowly tilts its bed upward to dispose of a 95 kg steel cabinet. For small angle of tilt the crate stay put,but when the tilt angle exceeds 23.2° the steel cabinet begins to slide.What is the coefficient of static friction between the bed of the truck and the steel cabinet?
Answer:
The value is [tex]\mu =0.4286[/tex]
Explanation:
From the question we are told that
The mass of the steel cabinet is [tex]m = 95 \ kg[/tex]
The threshold angle is [tex]\theta = 23.2^o[/tex]
Generally at the point just before the steel cabinet starts to slide
The horizontal force on the steel cabinet is equal to the frictional force that is
[tex]F_f = F_h[/tex]
Here [tex]F_h[/tex] is the horizontal force which is mathematically represented as
[tex]F_h = m * g cos (theta )[/tex]
and [tex]F_f = \mu N[/tex]
Here N is the normal force acting on the steel cabinet and this is mathematically represented as
[tex]N = mg sin (\theta )[/tex]
=> [tex] m * g cos (theta )= mg sin (\theta ) * \mu [/tex]
=> [tex]\mu = tan (\theta )[/tex]
=> [tex]\mu = tan (23.2)[/tex]
=> [tex]\mu =0.4286[/tex]
The coefficient of static friction between the bed of the truck and steel cabinet is 0.43.
The given parameters;
mass of the steel, m = 95 kgangle of inclination, θ = 23.2⁰The coefficient of static friction between the bed of the truck and steel cabinet is calculated as follows;
[tex]\Sigma F = 0\\\\mg sin(\theta) - \mu mg cos(\theta) = 0\\\\\mu mg cos(\theta ) = mg sin(\theta)\\\\\mu cos(\theta) = sin(\theta)\\\\\mu = \frac{sin(\theta)}{cos(\theta)} \\\\\mu = tan (\theta)\\\\\mu = tan \ (23.2)\\\\\mu = 0.43[/tex]
Thus, the coefficient of static friction between the bed of the truck and steel cabinet is 0.43.
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A train travels from Boston to New York. It travels at a speed of 180 km/h for two hours, speeds up to 200 km/h for the next four hours and then slows down to 120 km/h for the next six hours. What is the average speed of the train for this trip?
Answer:
156 2/3 km/hr
Explanation:
Average speed is found by dividing total distance by total time.
180 km/hr in 2 hrs is 360 miles
200 km/hr in 4 hrs is 800 miles
120 km/hr in 6 hrs is 720 miles
Total time is 12 hrs; Total distance 1880 hrs
Divide distance by time and you have 156 2/3 km/hr. This is your average speed.
A child (mass Me) pulls a sled (mass Ms) holding a baby (mass m) across the snow (assume the snow is frictionless). When the child starts the sled moving the baby brother slips off the sled instead of moving with the sled. The child tries again with a slightly smaller force and the baby stays on the sled due to the friction between the baby and the sled. Write a symbolic solution for the coefficient offriction between the baby and the sled if the maximum acceleration ofthe sled for the baby to stay on the sled is a. The solution may include the variables MC: Ms, m: a and g but does not need to have all ofthem_ The computer Ivill not recognize any other variables. Do not include any numbers (or the in your answer). Fill in the blank
Answer:
symbolic solution for the coefficient of friction between the baby and the sled is
[tex] \mu = \frac{m + M_s}{m} * \frac{a}{g}[/tex]
Explanation:
From the question we are told that
The mass of the boy is [tex]M_e =[/tex]
The mass of the shed is [tex]M_s[/tex]
The mass of the baby is [tex]m[/tex]
The maximum acceleration for the baby to stay is a
Generally the frictional force between the baby and the shed is mathematically represented as
[tex]F_f = \mu N[/tex]
Here N is the normal force acting on the baby which is mathematically represented as
[tex]N = m * g[/tex]
=> [tex]F_f = \mu * m * g[/tex]
Now for the baby not the slip off the shed the frictional force between the baby and the shed must be equal to the the force applied by the child
The force applied by the child is mathematically represented as
[tex]F = [M_s+m] * a[/tex]
So
[tex] \mu * m * g = [M_s+m] * a[/tex]
=> [tex] \mu = \frac{m + M_s}{m} * \frac{a}{g}[/tex]
the natural direction of heat flow between two reservoirs depends on ....
Answer:
a. their temperatures
Explanation:
Hello.
In this case, among the options:
a. their temperatures .
b. their internal energy contents .
c. their pressures .
d. whether they are in the solid, liquid, or gaseous state.
We must remember that the driving force assisting heat transfer is the temperature difference which states that the heat flows from higher temperatures to lower temperatures based on the second law of thermodynamics. Therefore answer is a. their temperatures .
Best regards.
which one is not a derived unit?
1. Hertz
2. mol
3. Watt
4. Newton
Answer:
mol
Explanation:
this is the movie i have never watched(interesting) adjective
What type of fossils were found near Macon Georgia?
Answer:
I believe whale fossils were found.
List the 4 materials that would light up this light bulb when dropped onto the crocodile clips. In 1 -2 sentences describe why it caused the light to turn on using these 4 key terms Conductors, circuit, electrons and flow.
Answer:
Ok I might be wrong but I think its the screwdriver, screw, key and the fork
Explanation:
Why because they all have metal in them if am wrong am sorry buddy i was struggling on the same thing
A small truck has a mass of 2145 kg. How much work is required to decrease the speed of the vehicle from 25.0 m/s to 12.0 m/s on a level road?
Answer:
The work required is -515,872.5 J
Explanation:
Work is defined in physics as the force that is applied to a body to move it from one point to another.
The total work W done on an object to move from one position A to another B is equal to the change in the kinetic energy of the object. That is, work is also defined as the change in the kinetic energy of an object.
Kinetic energy (Ec) depends on the mass and speed of the body. This energy is calculated by the expression:
[tex]Ec=\frac{1}{2} *m*v^{2}[/tex]
where kinetic energy is measured in Joules (J), mass in kilograms (kg), and velocity in meters per second (m/s).
The work (W) of this force is equal to the difference between the final value and the initial value of the kinetic energy of the particle:
[tex]W=\frac{1}{2} *m*v2^{2}-\frac{1}{2} *m*v1^{2}[/tex]
[tex]W=\frac{1}{2} *m*(v2^{2}-v1^{2})[/tex]
In this case:
W=?m= 2,145 kgv2= 12 [tex]\frac{m}{s}[/tex]v1= 25 [tex]\frac{m}{s}[/tex]Replacing:
[tex]W=\frac{1}{2} *2145 kg*((12\frac{m}{s} )^{2}-(25\frac{m}{s} )^{2})[/tex]
W= -515,872.5 J
The work required is -515,872.5 J
The amount of work needed by the vehicle to decrease its speed from 25 m/s to 12 m/s is 515872.5 J.
The amount of work required by the truck to decrease its speed can be calculated using the formula below.
Formula:
W = m(u²-v²)/2............. Equation 1Where:
W = amount of work required to decrease the speed of the vehicle.m = mass of the truckv = Final speedu = initial speed.From the question,
Given:
m = 2145 kgv = 12 m/su = 25 m/s.Substitute these values into equation 1
W = 2145(25²-12²)²/2W = 2145(481)/2W = 515872.5 J.Hence, The amount of work needed by the vehicle to decrease its speed from 25 m/s to 12 m/s is 515872.5 J.
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A car travels 90 meters due north in 15 seconds. Then the car
turns around and travels 40 meters due south in 5 seconds.
What is the magnitude of the average velocity of the car during
this 20 second interval?
C. 6.5
a. 2.5 m/sb. 5.0 m/s
d. 7.0 m/s
m/s
Physics Vectors-- Please could you help me ? For first question.
Dillon wants to go to the park to play basketball. To get to the park, he must travel 9 km East, and then 6 km South, then 9 Km West. Calculate the distance
Answer:
24 km
Explanation:
9 + 9 + 6 = 24
a blackbody is at temperature of 500°C . What would be its temperature in Kelvin for it to radiate twice as much energy per second?
Answer:
Its temperature in Kelvin for it to radiate twice as much energy = [tex]919.257k[/tex]Explanation:
Energy = [tex]6AT^4[/tex]
therefore,
[tex]\frac{E_1}{E_2} = \frac{T_1^4}{T_2^4}[/tex]
where [tex]E_2 = 2E_1[/tex]
therefore,
[tex]\frac{E_1}{2E_1} = \frac{(500+273)^4}{T_2^4}\\\\T_2 = 919.257k\\\\T_2 = 646.257^oC[/tex]
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The achievement of lifting a rocket off the ground and into space can be explained by
Answer:
The achievement of lifting a rocket off the ground and into space can be explained by Newton's third law of motion. What is required for a rocket to lift off into space? Thrust is required for a rocket to lift off into space, ... An object that travels around another object in space is called a satellite.
Explanation:
HELP! IDENTIFY AND DRAW A CONCLUSION FOR THIS PROBLEM PLS! ASAP.
Answer:
the conclusion is that the plant that had been given fertilizer B grew more than the plant with fertilizer A and the plant without fertilizer. so in conclusion fertilizer B is better for growing plants fastly.
the problem is that you noticed your tomatoes were not growing properly.
Hope this helps!❤
I WILL MARK YOU AS BRAINLIEST IF RIGHT
A 1250 kg car was traveling at 10 m/s toward a traffic signal when the light suddenly turned red. The driver slammed on his brakes, stopping the car in 3.3 seconds. What was the acceleration of the car ?
Answer:
a = - 3 m/s^2 (negative 3 meters per second squared)
Explanation:
We use the formula for acceleration as the change in velocities (from initial velocity "vi" to final velocity "vf") divided the time "t" it took. In our case:
a = (vf - vi) / t = (0 - 10) / 3.3 = -10 /3.33 = -3 m/s^2
How does energy from the sun travel to earth .
Answer:
through uv light
If a drag racing car accelerated at 69 miles per second in 0.25 s, what is the acceleration of the car
Answer:
acceleration is : 276 mi/s^2
(276 miles per second squared)
Explanation:
We use the formula for acceleration (a) which is the change in velocity divided by the time it took to change it:
a = (vf - vi) / t
where "vf" stands for final velocity, "vi" for initial velocity, and "t" for the time it took for the velocity to change.
In our case:
a = (69 - 0) / 0.25 = 276 mi/s^2
(276 miles per second squared)
Suggest one reason why the bricklayer needs a higher energy diet than the computer operator
Answer:
he needs more because he is doing more exercise this means he is working his body more and he needs more energy than someone he is sitting in an office. The computer operator would not need as much energy as the brick layer.
PLEASE HELP!!!How would you describe the motion of a transverse wave?
Answer:
The motion of a transverse wave would be described as perpendicular to the wave direction.
Explanation:
The motion of a transverse wave is perpendicular to the wave propagation.
What is transverse wave?
A transverse wave is an oscillating wave in physics that advances in the opposite direction of its oscillations. A longitudinal wave, on the other hand, moves in the direction of its oscillations. Transverse waves include water waves.
The waves that can be made on a horizontal length of string by anchoring one end and moving the other end up and down provide a straightforward example. The waves that are produced on a drum's membrane serve as another illustration. Each point in the membrane moves up and down, perpendicular to the membrane plane, as the waves move in directions parallel to the membrane plane.
Another example of a transverse wave is light, which has electric and magnetic fields as oscillations.
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HELP PLZ HURRY :((( I NEED IT BY TONIGHT
Answer:
Please see attached image
Explanation:
Calculate the acceleration of a student riding his bicycle in a straight line that speeds up from 4 m/s to 6 m/s in 5 seconds.
Which most likely has the greatest conductivity?
a warm plastic rod
a cool rubber tube
a cool lead metal strip
a warm copper wire
Answer:
Which most likely has the greatest conductivity?
a warm plastic rod
a cool rubber tube
a cool lead metal stripa warm copper wire
Explanation:
The warm copper wire most likely has the greatest conductivity.
What is conductivity?Conductivity is a measure of how easily a material can conduct electricity. Metals like copper are known for having high electrical conductivity due to the presence of free electrons that can move easily through the material when an electric field is applied.
Non-metallic materials like plastic and rubber generally have low electrical conductivity because they do not have free electrons available for conduction.
Additionally, the temperature of the material can also affect its conductivity. As temperature increases, the movement of atoms and molecules in the material also increases, which can cause a decrease in electrical conductivity.
Therefore, of the materials listed, the warm copper wire is most likely to have the greatest conductivity due to its metallic properties and elevated temperature.
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A reversible power cycle operates with a thermal efficiency of 75%. The cycle receives energy input by heat from a thermal reservoir at 1200K. What is the temperature, in K, of the low temperature thermal reservoir
Answer:
The temperature of the low temperature thermal reservoir is 300 K.
Explanation:
All reversible power cycles are equivalent to the Carnot's cycle, whose equation for efficiency is:
[tex]\eta_{th} =1-\frac{T_{L}}{T_{H}}[/tex] (Eq. 1)
Where:
[tex]\eta_{th}[/tex] - Thermal efficiency, dimensionless.
[tex]T_{H}[/tex] - High temperature reservoir, measured in Kelvin.
[tex]T_{L}[/tex] - Low temperature reservoir, measured in Kelvin.
Now we proceed to clear the low temperature reservoir within:
[tex]\frac{T_{L}}{T_{H}} = 1-\eta_{th}[/tex]
[tex]T_{L} = (1-\eta_{th})\cdot T_{H}[/tex]
If [tex]\eta_{th} = 0.75[/tex] and [tex]T_{H} = 1200\,K[/tex], then:
[tex]T_{L} = (1-0.75)\cdot (1200\,K)[/tex]
[tex]T_{L} = 300\,K[/tex]
The temperature of the low temperature thermal reservoir is 300 K.
