Answer:
(a) The resistor disspates 103680 joules during a 24-hour period.
(b) The heat flux of the resistor is approximately 4340.589 watts per square meter.
(c) The fraction of heat dissipated from the top and bottom surfaces is 0.045.
Explanation:
(a) The amount of heat dissipated ([tex]Q[/tex]), measured in joules, by the cylindrical resistor is the power multiplied by operation time ([tex]\Delta t[/tex]), measured in hours. That is:
[tex]Q = \dot Q \cdot \Delta t[/tex] (1)
If we know that [tex]\dot Q = 1.2\,W[/tex] and [tex]\Delta t = 86400\,s[/tex], then the amount of heat dissipated by the resistor is:
[tex]Q = (1.2\,W)\cdot (86400\,s)[/tex]
[tex]Q = 103680\,J[/tex]
The resistor disspates 103680 joules during a 24-hour period.
(b) The heat flux ([tex]Q'[/tex]), measured in watts per square meter, is the heat transfer rate divided by the area of the cylinder ([tex]A[/tex]), measured in square meters:
[tex]Q' = \frac{\dot Q}{A}[/tex] (2)
[tex]Q' = \frac{\dot Q}{\frac{\pi}{2}\cdot D^{2}+\pi\cdot D \cdot h }[/tex] (3)
Where:
[tex]D[/tex] - Diameter, measured in meters.
[tex]h[/tex] - Length, measured in meters.
If we know that [tex]\dot Q = 1.2\,W[/tex], [tex]D = 4\times 10^{-3}\,m[/tex] and [tex]h = 2\times 10^{-2}\,m[/tex], the heat flux of the resistor is:
[tex]Q' = \frac{1.2\,W}{\frac{\pi}{2}\cdot (4\times 10^{-3}\,m)^{2}+\pi\cdot (4\times 10^{-3}\,m)\cdot (2\times 10^{-2}\,m) }[/tex]
[tex]Q' \approx 4340.589\,\frac{W}{m^{2}}[/tex]
The heat flux of the resistor is approximately 4340.589 watts per square meter.
(c) Since heat is uniformly transfered, then the fraction of heat dissipated from the top and bottom surfaces ([tex]r[/tex]), no unit, is the ratio of the top and bottom surfaces to total surface:
[tex]r = \frac{\frac{\pi}{2}\cdot D^{2}}{A}[/tex] (3)
If we know that [tex]A \approx 2.765\times 10^{-4}\,m^{2}[/tex] and [tex]D = 4\times 10^{-3}\,m[/tex], then the fraction is:
[tex]r = \frac{\frac{\pi}{2}\cdot (4\times 10^{-3}\,m)^{2} }{2.765\times 10^{-4}\,m^{2}}[/tex]
[tex]r = 0.045[/tex]
The fraction of heat dissipated from the top and bottom surfaces is 0.045.
Tasks
Task 2 - Compare and contrast the use of D'Alembert's principle with
the principle of conservation of energy to solve an
engineering problem
A motor vehicle having a mass of 800 kg is at rest on an incline of 1 in 8 when the
brakes are released. The vehicle travels 30 m down the incline against a constant
frictional resistance to motion of 100 N where it reaches the bottom of the slope.
a) Using the principle of conservation of energy, calculate the velocity of the
vehicle at the bottom of the incline.
b) Using an alternative method that does not involve a consideration of energy,
cacluate the velocity of the vehicle at the bottom of the incline.
c) Discuss the merits of the two methods you have used for parts a) and b) of
this question. Justify the use of an energy method for these types of
problems.
Answer:
NE DIYON INGILIZ MISIN SEN
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
what are the precautions to be taken while performing a rectangular glass prism experiment
Answer:
PRECAUTIONS
-The refracting faces of the glass prism should be smooth, transparent and without any air bubble or broken edge. ...
-Use a sharp pencil to draw boundary of the prism and rays of light.
-The alpins should have sharp tip and should be fixed exactly vertical to the plane of the paper.
Explanation:
Please give thanks to all my answers and please mark as brilliant and please follow me
How does Doppler ultrasound technology differ from ultrasound technology
that does not use the Doppler effect?
A. Doppler ultrasound collects data from moving objects.
B. Other ultrasound technology creates images, but Doppler
ultrasound does not.
C. Doppler ultrasound creates images, but other ultrasound
technology does not.
D. Doppler ultrasound is based on absorption of sound, and other
ultrasound technology is based on reflection.
Answer:
A. Doppler ultrasound collects data from moving objects
Explanation:
Did the test !!
Answer:A. Doppler ultrasound collects data from moving objects.
Explanation: just got it right
on my test
Q4. What is the speed of light in a block of glass that
has an Index of refraction of 1.11?
A skydiver is using wind to land on a target that is 120 m away horizontally. The skydiver starts from a height of 70 m and is falling vertically at a constant velocity of 7.0 m/s downward with their parachute open (terminal velocity). A horizontal gust of wind helps push them towards the target. What must be their total speed if they want to just hit their target
Answer:
13.9 m/s.
Explanation:
Since the vertical velocity of the skydiver is constant at v = 7.0 m/s, we find the time, t it takes him to drop from a height of h = 70 m.
So, distance = velocity time
h = vt
t = h/v = 70 m/7 m/s = 10 s
This is also the time it takes him to move horizontally a distance of d = 120 m to the target.
So, his horizontal velocity is v' = distance/time = d/t = 120m/10 s = 12 m/s.
Since both vertical and horizontal velocities are perpendicular, we add them vectorially to obtain the skydivers total speed, V.
So, V = √(v² + v'²)
= √((7.0 m/s)² + (12.0 m/s)'²)
= √(49 m²/s² + 144 m²/s²)
= √(193 m²/s²)
= 13.9 m/s.
The direction of this velocity is Ф = tan⁻¹(v/v')
= tan⁻¹(7 m/s/12 m/s)
= tan⁻¹(0.5833)
= 30.3°
What makes electromagnets useful for sorting metals in recycling centers?
O A. The current can be turned on to pick up items containing all
metals and turned off to drop them.
O B. The current can be turned off to pick up items containing all
metals and turned off to drop them.
O C. The current can be turned on to pick up items containing iron and
turned off to drop them.
D. The current can be turned off to pick up items containing iron and
turned on to drop them.
C
It is right because I took this and I got this answer correct
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
how can you decrease the numbers
of calories you consume
Answer: by eating less of the recommendEd servings
Explanation:
This is from P.E , que some please help me
Answer:
I know that 2 is called a foul I dont know about 1 though
A 10,000 g body falls from a height of 20 m. Calculate the potential energy when it is at a height of 10 m
Answer:
Ep = 980 J
Explanation:
First, grams must be converted to kilograms. So, we must divide the value of the mass, by 1000.
[tex]\boxed{\frac{10000}{1000}=\boxed{10kg}}[/tex] ---------- Converted to kg.==================================================================
Data:
Mass (m) = 10 kgGravity (g) = 9.8 m/s²Height (h) = 10 mPotential Energy (Ep) = ?Use formula:
Ep = m * g * hReplace:
Ep = 10 kg * 9.8 m/s² * 10 mMultiply operations, with units:
Ep = 980 JWhat is the potential energy?
The potential energy is 980 Joules.
What simple machine can best be described as "a simple machine that uses an inclined plane wrapped around a rod"?
a wedge
a screw
a wheel and axle
a lever
Answer:
It is a screw.
Explanation:
Iron has a specific heat of o.45 J/g °C. Removing -1.16 E 2 J of energy lowered the temperature of iron from 89 °C to 26.41 °C. What was the mass of the iron?
Answer:
m = 4.11 grams
Explanation:
Given that,
The specific heat of Iron, c = 0.45 J/g°C
Heat removed, [tex]Q=1.16\times 10^2\ J[/tex]
Initial temperature, [tex]T_i=89^{\circ} C[/tex]
Final temperature, [tex]T_f=26.41^{\circ} C[/tex]
We need to find the mass of the iron. We know that the heat removed in terms of specific heat is given by :
[tex]Q=mc\Delta T\\\\m=\dfrac{Q}{c\Delta T}\\\\m=\dfrac{-1.16\times 10^2}{0.45\times (26.41-89)}\\\\m=4.11\ g[/tex]
So, the mass of the iron is 4.11 grams.
A spacecraft and a staellite are at diametrically opposite position in the same circular orbit of altitude 500 km above the earth. As it passes through point A, the spacecraft fires its engine for a short interval of time to increase its speed and enter an elliptical orbit. Knowing that the spacecraft returns to A at the same time the satellite reaches A after completing one and a half orbits, determine (a) the increase in speed required, (b) the periodic time for the elliptic orbit
Answer:
Hello the diagram related to your question is attached below
answer: a) 851 m/s
b) 8506.1 secs
Explanation:
calculate the periodic time of the satellite using the equation below
t = [tex]\frac{2\pi }{R} \sqrt{\frac{(R+h)^{3} }{g} }[/tex] -- ( 1 )
where ; R = 6370 km
h = 500 km
g = 9.81 m/s^2
input given values into equation 1
t = 5670.75 secs
next calculate the periodic time taken by the space craft
a) determine the increase in speed
V = v - [tex]\sqrt{\frac{gR^2}{R + h} }[/tex]
where ; v = 8463 m/s , R = 6370 km, h = 500 km
V = 851 m/s
b) Determine the periodic time for the elliptic orbit
τ = [tex]\frac{3t}{2}[/tex]
= [tex]\frac{3*5670.76}{2}[/tex] = 8506.1 secs
attached below is the remaining part of the detailed solution
A certain brand of hotdog cooker works by applying a potential difference of 144 V across opposite ends of a hot dog and allowing it to cook by means of the thermal energy produced. The current is 10.5 A, and the energy required to cook one hot dog is 60.6 kJ. If the rate at which energy is supplied is unchanged, how long will it take to cook three hot dogs simultaneously
Answer:
120.237 seconds
Explanation:
Given that:
V = 144 V
I = 10.5 A
H = 60.6 kJ
Using the formula:
H = I²RT
From H = I²RT; making T the subject, we have:
[tex]T = \dfrac{H}{I^2R}[/tex]
where;
[tex]R = \dfrac{V}{I}[/tex]
∴
[tex]T = \dfrac{H}{V \times I}[/tex]
[tex]T = \dfrac{60.6 \times 10^3 }{144 \times 10.5}[/tex]
T = 40.079
[tex]T_{neq} = 3T[/tex]
[tex]T_{neq} =3 \times 40.079[/tex]
[tex]\mathbf{T_{neq} =120.237 \ sec}[/tex]
Please answer the question
Answer:
D
Explanation:
He walked a shorter distance, she walked a longer distance but got that wing thingies
What do you call the height of a wave?
a. wavelength
b. frequency
c. amplitude
d. resonance
Answer:
amplitude is the answer
Help me out please. It’d be greatly appreciated
Answer:
Option D
2Na + Cl₂ —> 2NaCl
Explanation:
We'll begin by stating the law of conservation of matter.
The law of conservation of matter states that matter can neither be created nor destroyed during a chemical reaction but can be transferred from one form to another.
For an equation to comply with the law of conservation of matter, the number of atoms of each element must be the same on both side of the equation. This simply means that the equation must be balanced!
NOTE: An unbalanced equation simply means matter has been created or destroyed.
Now, we shall determine which equation is balanced. This can be obtained as follow:
For Option A
Na + Cl₂ —> 2NaCl
Reactant:
Na = 1
Cl = 2
Product:
Na = 2
Cl = 2
Thus, the equation is not balanced!
For Option B
2Na + 2Cl₂ —> 2NaCl
Reactant:
Na = 2
Cl = 4
Product:
Na = 2
Cl = 2
Thus, the equation is not balanced!
For Option C
2Na + Cl₂ —> NaCl
Reactant:
Na = 2
Cl = 2
Product:
Na = 1
Cl = 1
Thus, the equation is not balanced!
For Option D
2Na + Cl₂ —> 2NaCl
Reactant:
Na = 2
Cl = 2
Product:
Na = 2
Cl = 2
Thus, the equation is balanced!
From the above illustrations, only option D has a balanced equation. Thus, option D illustrate the law of conservation of matter.
2. A force of 10 N is applied to an object which accelerates at a rate of 2m/s2. What is the mass
of the object?
(10 Points)
10 kg
5 kg
2 kg
20 kg
Explain two reasons why astronomers are continually building larger and larger telescopes. Explain two reasons why astronomers are continually building larger and larger telescopes. Larger telescope mirrors have a larger surface area and can therefore collect more light, which makes faint objects bright enough to detect. Also, larger telescope mirrors produce more scattering of light due to diffraction, which contributes to better angular resolution. Larger telescope mirrors have a larger surface area and can therefore collect more light, which contributes to better angular resolution. Also, larger telescope mirrors produce more scattering of light due to diffraction, which makes faint objects bright enough to detect. Larger telescope mirrors have a larger surface area and can therefore collect more light, which contributes to better angular resolution. Also, larger telescope mirrors produce less scattering of light due to diffraction, which makes faint objects bright enough to detect. Larger telescope mirrors have a larger surface area and can therefore collect more light, which makes faint objects bright enough to detect. Also, larger telescope mirrors produce less scattering of light due to diffraction, which contributes to better angular resolution.
Answer:
* Larger mirrors collect more light and therefore fainter and more distant objects can have enough intensity to be detected
* arger mirrors decreases the angle of dispersion giving a better resolution of the bodies
Explanation:
Refracting telescopes get bigger every day for two main reasons.
* Larger mirrors collect more light and therefore fainter and more distant objects can have enough intensity to be detected
* the diffraction process for circular apertures is given by
θ = 1.22 λ / D
where d is the diameter of the mirror, therefore having larger mirrors decreases the angle of dispersion giving a better resolution of the bodies
T Or F- True or False There three types of cloud's are .
Answer:
There are three main cloud types.
The foundation consists of 10 major cloud types. In addition to cirrus, stratus, cumulus, and nimbus clouds, there are cirrostratus, cirrocumulus, altostratus, altocumulus, stratocumulus, nimbostratus, and cumulonimbus clouds. The following table places these cloud types into the four major cloud groups.
Explanation:
So false, depends what you have learned and your grade level ig
You are walking on a moving walkway in the airport. The length of the walkway is 59.1 m. If your velocity relative to the walkway is 2.35 m/s, and the walkway moves with a velocity of 1.85 m/s, how long will it take you to reach the other end of the walkway
Answer:
14.1seconds approx
Explanation:
Given data
Distance= 59.1m
Your velocity= 2.35m/s
Walkway velocity= 1.85m/s
Total velocity= 2.35+1.85= 4.2m/s
We know that
Velocity= distance/time
time= distance/velocity
substitute
time= 59.1/4.2
time= 14.07
time=14.1seconds approx
Hence the time is 14.1seconds approx
A plane wishes to fly due north to an airport which is 205 km away. The plane can fly at a speed in still air of 220 km/h. A wind of 43 km/h blows from east to west.
a. In which direction,relative to north, should the plane head to reach it’s destination?
b. How long does this take?
Answer:
nique ta mama
Explanation:
Question 18 of 25
Which type of reaction is shown in this energy diagram?
Energy
Products
Activation
Energy
Reoctants
to
ti
Time
A. Endothermic, because the products are lower in energy
B. Exothermic, because the reactants are lower in energy
C. Endothermic, because the reactants are lower in energy
D. Exothermic, because the products are lower in energy
Answer:
Endothermic, because the reactants are lower in energy (C)
Explanation:
From the graph, you can see the energy of the products is higher than the energy of the reactants. If you recall that when the enthalpy change Eproducts is gretater than Ereactants, the reaction is said to be endothermic.
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
Three people pull simultaneously on a stubborn donkey. Jack pulls eastward with a force of 80.5 N, Jill pulls with 81.7 N in the northeast direction, and Jane pulls to the southeast with 131 N. (Since the donkey is involved with such uncoordinated people, who can blame it for being stubborn
Answer:
F = 233.52 N, θ' = 351.41º
Explanation:
In this exercise we must find the net force applied on the donkey.
For this we use Newton's second law, where we create a reference frame with the horizontal x axis
let's decompose the forces
Jack
= 80.5 N
Jill
cos 45 = F_{2x} / F₂2
sin 45 = F_{2y} / F₂2
F_{2x} = F₂ cos 45
F_{2y} = F₂ sin 45
F_{2x} = 81.7 cos 45 = 57.77 N
F_{2y} = 81.7 sin 45 = 57.77 N
Jane
cos (270 + 45) = F_{3x} / F₃3
sin 315 = F_{3y} / F₃
F_{3x} = 131 cos 315 = 92.63 N
F_{3y} = 131 sin 315 = -92.63 N
the force can be found in each axis
X axis
F_{x} = F_{1x} + F_{2x} + F_{3x}
F_{x} = 80.5 +57.77 + 92.63
F_{x} = 230.9 N
Axis y
F_{y} = F_{1y} + F_{2y} + F_{3y}
F_{y} = 0 + 57.77 -92.63
F_{y} = -34.86 N
we can give the result in two ways
a) F = (230.9 i ^ - 34.86 j ^) N
b) in the form of module and angle
we use the Pythagorean theorem
F = √(Fₓ² + F_{y}²
F = √(230.9² + 34.86²)
F = 233.52 N
let's use trigonometry for the angle
tan θ = [tex]\frac{F_y}{F_x} }[/tex]
θ = tan⁻¹ (\frac{F_y}{F_x} })
θ = tan⁻¹ (-34.86 / 230.9)
θ = -8.59º
if we measure this angle from the positive side of the x-axis counterclockwise
θ' = 360 -θ
θ‘= 360- 8.59
θ' = 351.41º
A ball is dropped from a building taking 3sec to fall to the ground. Calculate:
Speed when falling to the ground
The height of the building
Answer:
Vf = 29.4 m/s
h = 44.1 m
Explanation:
Data:
Initial Velocity (Vo) = 0 m/sGravity (g) = 9.8 m/s²Time (t) = 3 sFinal Velocity (Vf) = ?Height (h) = ?==================================================================
Final Velocity
Use formula:
Vf = g * tReplace:
Vf = 9.8 m/s² * 3sMultiply:
Vf = 29.4 m/s==================================================================
Height
Use formula:
[tex]\boxed{h=\frac{g*(t)^{2}}{2}}[/tex]Replace:
[tex]\boxed{h=\frac{9.8\frac{m}{s^{2}}*(3s)^{2}}{2}}[/tex]Multiply time squared:
[tex]\boxed{h=\frac{9.8\frac{m}{s^{2}}*9s^{2}}{2}}[/tex]Simplify the s², and multiply in the numerator:
[tex]\boxed{h=\frac{88.2m}{2}}[/tex]It divides:
[tex]\boxed{h=44.1\ m}[/tex]What is the velocity when falling to the ground?
The final velocity is 29.4 meters per seconds.
How high is the building?
The height of the building is 44.1 meters.
To have the highest magnification in a telescope, the focal length of the objective lens should be _________ and the focal length of the eyepiece lens should be ________. To have the highest magnification in a telescope, the focal length of the objective lens should be _________ and the focal length of the eyepiece lens should be ________. small; small small; large large; small large; large
Answer:
Large; small.
Explanation:
A telescope can be defined as an optical instrument or device which comprises of a curved mirror and lenses used for viewing distant objects i.e objects that are very far away such as stars and other planetary bodies. The first telescope was invented by Sir Isaac Newton.
To have the highest magnification in a telescope, the focal length of the objective lens should be large and the focal length of the eyepiece lens should be small.
This ultimately implies that, the eyepiece lens has a small focal length while the objective lens has a large focal length.
After watching this video, Blake, a student in an introductory physics class, makes the following claim: The acceleration and velocity of the glider are both momentarily zero when the glider changes direction. The velocity of the glider must be zero for an instant when the glider changes direction. Because the velocity is zero, the acceleration must also be zero. 1. Respond to Blake's claim. Which parts, if any do you agree with, and which parts do you not agree with
Answer:
Please see below as the answer is self- explanatory.
Explanation:
Any time that an object changes direction (from leftward to rightwward, or from upward to downward) the velocity must be zero just for one instant, when is on the verge of changing the direction.This is needed because velocity changes as a continuous function of time, so it needs to cross the t-axis when passing from positive to negative or vice versa.However, the claim that in the moment that velocity is zero, the acceleration is also zero, is false.Due to acceleration is the rate of change of velocity, and velocity is a vector, this means at any time there is a change of direction, there is an acceleration that is non-zero.For example, when an object that has been thrown upward, reaches to its maximum height, just one instant before starting to fall, the velocity becomes zero, but the acceleration (which causes the object to fall) is non-zero, due to it's the acceleration due to gravity.Which type of electromagnetic radiation is most likely to cause sunburn?
A. Ultraviolet
B. Visible light
C. Infrared
D. X-rays