An enclosure has an inside area of 50 m2, and its inside surface is black and is maintained at a constant temperature. A small opening in the enclosure has an area of 0.01 m2. The radiant power emitted from this opening is 48 W. What is the temperature of the interior enclosure wall, in K
Answer:
Explanation:
The enclosure will behave as black body . For black body , the formula for radiant energy is given by Stefan's law as follows
E = σ A T⁴ where σ = 5.67 x 10⁻⁸ W m⁻² T⁻⁴
Area A = .01 m²
E = 48 W
48 = .01 x 5.67 x 10⁻⁸ T⁴
T⁴ = 846.56 x 10⁸
T= 539 K
Following are the calculation to the temperature of the interior enclosure wall:
Given:
[tex]\to A_s=50\ m^2\\\\\to A_0=0.01\ m^2\\\\\to q_{rad}=48\ w\\\\\to \sigma = 5.67 \times 10^{-8}\ \frac{W}{m^{-2} T^{-4}} \\\\[/tex]
To find:
[tex]T_s=?[/tex]
Solution:
Using the value to calculate the surface is black radiates power:
[tex]\to q_{rad}=A_0 E_0 T_s\\\\\to q_{rad}=A_0 \sigma T_{s}^4\\\\\to 48=0.01 \times 5.67 \times 10^{-8} \times T_{s}^4\\\\[/tex]
[tex]\to T_{s}^4 =\frac{48}{0.01 \times 5.67 \times 10^{-8}} \\\\[/tex]
[tex]=\frac{48\times 100}{ 5.67 \times 10^{-8}} \\\\=\frac{48\times 100\times 10^{8} }{ 5.67 } \\\\=\frac{48\times 10^{10} }{ 5.67 } \\\\=8.46\times 10^{10} \\\\[/tex]
[tex]\to \bold{T_s=\pm 539.31 \ K}[/tex]
Therefore the final answer is "[tex]\bold{\pm 539.31 \ K}[/tex]".
Learn more:
brainly.com/question/10119413
Which type of electromagnetic radiation is most likely to cause sunburn?
A. Ultraviolet
B. Visible light
C. Infrared
D. X-rays
When observing the two diagrams, what is a concept shared by both?
Answer:
Convection
Explanation:
Convection refers to the transfer of heat by the actual movement of the heated molecules from the hot parts to the cooler parts.
Thus, the two diagrams show illustrate transfer of heat by the movement of molecules of a fluid.
This mode of heat transfer is known as convection. It is the concept illustrated by both diagrams.
INT Raindrops acquire an electric charge as they fall. Suppose a 2.0-mm-diameter drop has a charge of 12 pC; these are both very common values. In a thunderstorm, the electric field under a cloud can reach 15,000 N/C, directed upward. For a droplet exposed to this field, how do the magnitude and direction of the electric force compare to those of the weight force
Answer:
W = 2.3 10² [tex]F_{e}[/tex]
Explanation:
The force of the weight is
W = m g
let's use the concept of density
ρ= m / v
the volume of a sphere is
V = [tex]\frac{4}{3}[/tex] π r³
V = [tex]\frac{4}{3}[/tex] π (1.0 10⁻³)³
V = 4.1887 10⁻⁹ m³
the density of water ρ = 1000 kg / m³
m = ρ V
m = 1000 4.1887 10⁻⁹
m = 4.1887 10⁻⁶ kg
therefore the out of gravity is
W = 4.1887 10⁻⁶ 9.8
W = 41.05 10⁻⁶ N
now let's look for the electric force
F_e = q E
F_e = 12 10⁻¹² 15000
F_e = 1.8 10⁻⁷ N
the relationship between these two quantities is
[tex]\frac{W}{F_e}[/tex] = 41.05 10⁻⁶ / 1.8 10⁻⁷
\frac{W}{F_e} = 2,281 10²
W = 2.3 10² [tex]F_{e}[/tex]
therefore the weight of the drop is much greater than the electric force
Although the vocal tract is quite complicated, we can make a simple model of it as an open-closed tube extending from the opening of the mouth to the diaphragm, the large muscle separating the abdomen and the chest cavity. What is the length of this tube if its fundamental frequency equals a typical speech frequency of 230 Hz? Assume a sound speed of 350 m/s.
Answer:
0.76m
Explanation:
Given data
Frequency= 230Hz
speed= 350m/s
Since we are told that the frequency is the fundamental frequency n= 1
For a standing wave
Fn= nv/2L
n= 1
230= 1*350/2*L
230= 350/2L
cross multiply
2L= 350/230
2L=1.521
L=1.521/2
L=0.76m
Hence the length is 0.76m
What is the correct description for kinetic energy?Immersive Reader
(1 Point)
the energy an object has because of it temperature
the energy an object has because it is moving
the energy stored in an object because of its position
the energy stored in an object when you stretch or squash it
Answer:
The energy an object has because it is moving
Explanation:
It has been a while since I have talked about kinetic energy so I can't give you an explanation why that answer is right but it is.
At the instant the traffic light turns green, an automobile starts with a constant acceleration a of 2.70 m/s2. At the same instant a truck, traveling with a constant speed of 9.50 m/s, overtakes and passes the automobile. (a) How far beyond the traffic signal will the automobile overtake the truck
Answer:
66.85 m
Explanation:
We are given that
Acceleration ,a=[tex]2.7m/s^2[/tex]
Speed of truck, v=9.5 m/s
We have to find the distance beyond which the traffic signal will the automobile overtake the truck.
Initial speed of automobile, u=0
We know that
[tex]s=ut+\frac{1}{2}at^2[/tex]
Using the formula
[tex]s=0+\frac{1}{2}(27)t^2=\frac{27}{2}t^2[/tex]
For constant speed
Acceleration, a=0
Again
[tex]s=vt+0=9.5t[/tex]
[tex]9.5t=\frac{27}{2}t^2[/tex]
[tex]t=\frac{9.5\times 2}{2.7}=7.037s[/tex]
Substitute the value of t
[tex]x=9.5(7.037)=66.85m[/tex]
Hence, the distance beyond which the traffic signal will the automobile overtake the truck=66.85 m
What is the average speed of a car that travels 60 meters in 2
seconds?
Answer:
30 m/s
Explanation:
Speed is distance over time. 60 meters / 2 seconds, = 30 m/s.
A body moves on a coordinate line such that it has a position sequalsf(t)equalstsquaredminus4tplus3on the interval 0less than or equalstless than or equals7,with s in meters and t in seconds.a. Find the body's displacement and average velocity for the given time interval.b. Find the body's speed and acceleration at the endpoints of the interval.c. When, if ever, during the interval does the body change direction?
Answer:
A) Δf = - 49 m, B) v (7) = -56 m / s, a = - 8 m / s², C) t = 0.866 s
Explanation:
A) In this exercise ask to find the displacement and the average velocity, give the function of the movement
f (t) = - 4t² +3
and the range of motion 0≤ t ≤ 7
the displacement is
for t = 0
f (0) = 3
for t = 7 s
f (7) = - 4 7² +3
f (7) = -46 m
the total displacement is
Δf = f (7) - f (0)
Δf = -46 - 3
Δf = - 49 m
the average speed is defined as the displacement between the time interval
v = Df / Dt
v = -49 / 7
v = - 7 m / s
B) the speed and acceleration of the end points of the motion
the speed of defined by
v = [tex]\frac{dx}{dt}[/tex]
in this case
v = [tex]\frac{df}{dt}[/tex]
v = -8t
let's calculate
v (7) = -8 7
v (7) = -56 m / s
acceleration is defined by
a = [tex]\frac{dv}{dt}[/tex]
a = - 8 m / s²
acceleration is constant throughout the movement
C) the point where the direction changes.
This point is a point where the position goes from positive to negative, the point f = 0
0 = -4t² +3
t = √¾
t = 0.866 s
Can someone please help, ty!!
Will mark brainliest.
Answer:
#1 ( Balanced ) ( Rest)
#2 ( Unbalanced) ( Accelerating)
Explanation:
is
5
The specific heat of copper is 0.385 J/g
°C. How much thermal energy is required
to increase the temperature of a 20g
sample of copper from 20°C to 50°C?
Q = m CAT
A 154 )
B 231 )
C 308 )
D 385 )
Answer:
Required energy Q = 231 J
Explanation:
Given:
Specific heat of copper C = 0.385 J/g°C
Mass m = 20 g
ΔT = (50 - 20)°C = 30 °C
Find:
Required energy
Computation:
Q = mCΔT
Q = 20(0.385)(30)
Required energy Q = 231 J
A horizontal force of 120N is required to push a block across a floor at constant velocity, what is the net force acting on the block?
Answer:
a horizontal force of 120N to Push the block into the floor is called net force
Based on your graph, predict the length of pendulum that will give you a
period of 2.00s.
Answer:
About 1 meter
Explanation:
Base on your image, when the period is 2 (horizontal variable), the length of the pendulum is about 1 meter.
A certain wave has a compressions and rarefactions.How should this wave be classified?
A) As a longitudinal wave
B)As a surface wave
C)A transverse wave
D)As an electromagnetic wave
This question involves the concepts of compression and rarefraction.
This wave should be classified as "A) a longitudinal wave".
Types of WaveA surface wave is a mechanical wave which propagates on the boundary interface between two different media.
A longitudinal wave is the wave in which the direction of travel of the wave and medium are the same. This wave consists of compressions and rarefactions.
A transverse wave is the wave in which the direction of travel of the wave and medium are perpendicular to each other. It consists of crests and troughs.
An electromagnetic wave is the one which consists of electric field and magnetic field vibrating perpendicular to each other.
Hence, the wave with compressions and rarefactions is classified as a longitudinal wave.
Learn more about compressions and rarefactions here:
https://brainly.com/question/1326823
#SPJ2
In case A below, a 1 kg solid sphere is released from rest at point S. It rolls without slipping down the ramp shown, and is launched vertically into the air at point T. In case B, a 1 kg block slides without friction down an identically shaped ramp and is also launched vertically at point T. Select the statement that best describes which object will go higher after launch, and why
Answer:
the block reaches higher than the sphere
\frac{y_{sphere}} {y_block} = 5/7
Explanation:
We are going to solve this interesting problem
A) in this case a sphere rolls on the ramp, let's find the speed of the center of mass at the exit of the ramp
Let's use the concept of conservation of energy
starting point. At the top of the ramp
Em₀ = U = m g y₁
final point. At the exit of the ramp
Em_f = K + U = ½ m v² + ½ I w² + m g y₂
notice that we include the translational and rotational energy, we assume that the height of the exit ramp is y₂
energy is conserved
Em₀ = Em_f
m g y₁ = ½ m v² + ½ I w² + m g y₂
angular and linear velocity are related
v = w r
the moment of inertia of a sphere is
I = [tex]\frac{2}{5}[/tex] m r²
we substitute
m g (y₁ - y₂) = ½ m v² + ½ ([tex]\frac{2}{5}[/tex] m r²) ([tex]\frac{v}{r}[/tex])²
m g h = ½ m v² (1 + [tex]\frac{2}{5}[/tex])
where h is the difference in height between the two sides of the ramp
h = y₂ -y₁
mg h = [tex]\frac{7}{5}[/tex] ([tex]\frac{1}{2}[/tex] m v²)
v = √5/7 √2gh
This is the exit velocity of the vertical movement of the sphere
v_sphere = 0.845 √2gh
B) is the same case, but for a box without friction
starting point
Em₀ = U = mg y₁
final point
Em_f = K + U = ½ m v² + m g y₂
Em₀ = Em_f
mg y₁ = ½ m v² + m g y₂
m g (y₁ -y₂) = ½ m v²
v = √2gh
this is the speed of the box
v_box = √2gh
to know which body reaches higher in the air we can use the kinematic relations
v² = v₀² - 2 g y
at the highest point v = 0
y = vo₀²/ 2g
for the sphere
y_sphere = 5/7 2gh / 2g
y_esfera = 5/7 h
for the block
y_block = 2gh / 2g
y_block = h
therefore the block reaches higher than the sphere
[tex]\frac{y_{sphere}} {y_bolck} = 5/7[/tex]
As an electromagnetic wave travels, what is the relationship between the
magnetic field and the electric field along its path?
A. They are parallel to each other.
B. The angle between them decreases with an increase in energy
O C. The angle between them increases with an increase in energy.
D. They are at a 90° angle to each other.
Answer:
Its D
Explanation:
They are at a 90° angle to each other.
Do good on your tests :]
The answer is D) They are at a 90° angle to each other.
What is an electromagnetic wave?One of the waves which are propagated with the aid of simultaneous periodic versions of electrical and magnetic subject depth and consists of radio waves, infrared, seen mild, ultraviolet, X-rays, and gamma rays.
Radio waves, microwaves, seen light, and x-rays are all examples of electromagnetic waves that range very differently in wavelength. (a) Longer wavelength; (b) shorter wavelength. Electromagnetic waves are produced by means of the motion of electrically charged debris.
Learn more about electromagnetic waves here: https://brainly.com/question/25847009
#SPJ2
True or False:
Some stars appear dimmer than others. Dim stars are always further
away from us than bright stars.
Answer:
A star's brightness also depends on its proximity to us. The more distant an object is, the dimmer it appears.
Hearing rattles from a snake, you make two rapid displacements of magnitude 1.8 m and 2.4m. Draw sketches, roughly to scale, to show how your two displacements might add to give the following resultant of magnitudes.
a. 4.2 m
b. 0.6 m
c. 3.2 m
Answer:
The answer is a 4.2m
Explanation:
Given data
Please see attached the rough drawing for your reference.
From the drawing, you ran 18m west and 2.4m south
The displacement is
= 1.8+2.4
=4.2m
How fast would an object have to travel on the surface of Jupiter at the equator to keep up with the Sun (that is, so the Sun would appear to remain in the same position in the sky)? Use the facts that the radius of Jupiter is approximately 44,360 miles and its revolution is approximately 10 hours.
Answer:
27872.2 miles per hour
Explanation:
Given that :
Radius of Jupiter is approximately = 44,360 miles
Revolution is 10 hours ;
Jupiter makes one revolution in 10 hours :
Using the relation to obtain the velocity :
V = re
r = radius
w = 2π/T
Hence,
V = r * 2π/ T
V =44360 * 2 * π/10
V = 88720 * π/10
V = 278722.10 / 10
V = 27872.210
V = 27872.2 miles per hour
Based on the data, which statement describes the most reliable way to
encode and transmit data and tells why?
A. Digital waves are more reliable because they are less likely to
change when copied.
B. Analog waves are more reliable because they include a range of
values like the original.
C. Analog waves are more reliable because they are less likely to
change when copied.
D. Digital waves are more reliable because they are slightly different
from the original.
Answer:it’s A. right for ape x
Explanation:
Based on data, digital waves are more reliable because they are less likely to change when copied (Option A).
What is a wave?A wave is a periodic distortion capable of traveling through a suitable media (either air or water).
The waves can be classified according to their direction into transversal and perpendicular.In conclusion, based on data, digital waves are more reliable because they are less likely to change when copied (Option A).
Learn more on waves here:
https://brainly.com/question/15663649
#SPJ2
I have a massive rock weighing 3,000 Newtons but I can only accelerate it to 500 m/s2 what is its mass?
Answer:
6 kg
Explanation:
F=ma
F is Force(newtons)
m is mass(kg)
a is acceleration(m/s^2)
Plug in the numbers
3000 = m(500)
divide both sides by 500 to cancel out the 500.
3000/500=6
6 = m
6kg is the mass
A DC motor connected to a switch-mode dc-dc converter goes into regenerative braking mode. The average current being supplied by the dc motor is 20 A. In the equivalent circuit of the dc motor, Ea=103 V, Ra=0.19 Ohms, and La=4 mH. Calculate the average power flow into the converter. Round answer to the nearest whole number.
Answer:
The correct answer is "2524 W".
Explanation:
The given values are:
Ia = 20 A
Ea = 103 V
Ra = 0.19 Ω
La = 4 mH
According to KVL,
⇒ [tex]V_0=E_a-I_aR_a[/tex]
On substituting the given values in the above equation, we get
⇒ [tex]=103-(20)(0.19)[/tex]
⇒ [tex]=103-3.8[/tex]
⇒ [tex]=126.2 \ V[/tex]
Now,[tex]=126.2\times 20[/tex]
The average power flow into the converter will be:
⇒ [tex]P=V_0 I_a[/tex]
On substituting the given values, we get
⇒ [tex]=(126.2\times 20)[/tex]
⇒ [tex]=2524 \ W[/tex]
what kind of lens curve inward toward its center
Answer:
A concave lens is exactly the opposite with the outer surfaces curving inward, so it makes parallel light rays curve outward or diverge. That's why concave lenses are sometimes called diverging lenses.
Answer: A concave lens
A concave lens is exactly the opposite with the outer surfaces curving inward, so it makes parallel light rays curve outward or diverge. That's why concave lenses are sometimes called diverging lenses.
Hopes this helps :)
Hi everyone.
How are you all I hope you guys are fine.
question:why the symbol of Joule is capital (J)?
Answer:
The joule (symbol: J) is the basic SI unit of energy. A joule is equal to the kinetic energy of a kilogram mass moving at the speed of one meter per second (one joule is a kg⋅m2⋅s−2). ... Because it is named for a person, the first letter of the symbol is uppercase (J instead of j)
Explanation:
1 example of a conductor and 1 example of a insulator in your EVERYDAY world.
Answer: Examples of conductors include metals, aqueous solutions of salts (i.e., ionic compounds dissolved in water), graphite, and the human body. Examples of insulators include plastics, Styrofoam, paper, rubber, glass and dry air.
You are concerned about the moon roof on your new sports car. It seems to flex when driving at high speeds. Calculate how much net force the moon roof must withstand and in what direction. Assume the moon roof is flat with an area of 0.5 m^2 and the pressure and velocity over the moon roof is constant. Your driving speed is 20 m/s, and the velocity over the moon roof is 30 m/s. The pressure inside the car is 90,500 N/m^2 and the freestream pressure and density in front of the car are 90,000 N/m^2 and 1.1 kg/m^3.
Answer:
Explanation:
We shall apply Bernoulli's formula to solve the problem . It is as follows .
P + ρ gh + 1/2 ρ v² = constant .
P₁ + ρ gh + 1/2 ρ v₁² = P₂ + ρ gh + 1/2 ρ v₂²
P₁ + 1/2 ρ v₁² = P₂ + 1/2 ρ v₂²
P₁ - P₂ = 1/2 ρ (v₂² - v₁² )
= .5 x 1,1 ( 30² - 20² )
= 275 N / m²
velocity over moon roof is high , pressure will be lower there by 275 N / m²
Given pressure difference already existing = 90500 - 90000 = 500 N / m²
Additional pressure difference due to velocity difference = 275 N / m²
Total pressure difference = 275 + 500 = 775 N / m²
Area of roof = .5 m²
Total force acting upwards on the roof
= .5 x 775 N
= 387.5 N .
What does Fgrav or Fg mean when its next to a vector arrow?
6 An object can never have
A. a positive speed.
B. a negative speed.
C. a positive velocity.
D. a negative velocity.
Answer:
B
Explanation:
Speed is the magnitude of the velocity vector, so it can never be negative.
An object can never have a negative velocity. Therefore, option (D) is correct.
What is velocity?Velocity is a vector quantity that describes an object's speed and direction of motion. If an object is moving in a positive direction, it has a positive velocity. If it is moving in the opposite direction, it has a negative velocity.
However, an object can never have a negative speed. Speed is a scalar quantity that describes an object's rate of motion, and it is always positive. The speed of an object can be positive or negative, depending on the direction of its velocity, but the magnitude of its speed is always positive.
Learn more about velocity, here:
https://brainly.com/question/18084516
#SPJ6
Two children, Ferdinand and Isabella, are playing with a water hose on a sunny summer day. Isabella is holding the hose in her hand 1.0 meters above the ground and is trying to spray Ferdinand, who is standing 10.0 meters away. Will Isabella be able to spray Ferdinand if the water is flowing out of the hose at a constant speed v0 of 3.5 meters per second?
Answer:
Isabella will not be able to spray Ferdinand.
Explanation:
We'll begin by calculating the time taken for the water to get to the ground from the hose held at 1 m above the ground. This can be obtained as follow:
Height (h) = 1 m
Acceleration due to gravity (g) = 9.8 m/s²
Time (t) =.?
h = ½gt²
1 = ½ × 9.8 × t²
1 = 4.9 × t²
Divide both side by 4.9
t² = 1/4.9
Take the square root of both side
t = √(1/4.9)
t = 0.45 s
Next, we shall determine the horizontal distance travelled by the water. This can be obtained as follow:
Horizontal velocity (u) = 3.5 m/s
Time (t) = 0.45 s
Horizontal distance (s) =?
s = ut
s = 3.5 × 0.45
s = 1.58 m
Finally, we shall compare the distance travelled by the water and the position to which Ferdinand is located to see if they are the same or not. This is illustrated below:
Ferdinand's position = 10 m
Distance travelled by the water = 1.58 m
From the above, we can see that the position of the water (i.e 1.58 m) and that of Ferdinand (i.e 10 m) are not the same. Thus, Isabella will not be able to spray Ferdinand.
A swimmer, capable of swimming at a speed of 1.60 m/s in still water (i.e., the swimmer can swim with a speed of 1.60 m/s relative to the water), starts to swim directly across a 1.25-km-wide river. However, the current is 0.549 m/s, and it carries the swimmer downstream. (a) How long does it take the swimmer to cross the river
Answer:
t = 781.25 s
Explanation:
This is an exercise in velocity composition, if we set a reference system where the x-axis is perpendicular to the river and the y-axis is parallel to the river.
The swimmer has a velocity on the x axis
vx = 1.60 m / s
a velocity on the y axis, created by the current of the river
vy = 0.549 m / s
time is a scalar, therefore the time it takes to cross the river is the same time it creates the displacement in e; Axis y
X axis
vₓ = x / t
t = x / vₓ
t = 1250 / 1.6
t = 781.25 s
in this time a distance has descended
y = v_y t
y = 0.549 781.25
y = 428.9 m
