Answer:
Explanation:
a )
We shall apply Wein's displacement law
λm x T = b where λm is wavelength of radiation having maximum intensity
T is absolute temperature of body , and b is a constant
b = 2898 μm-K
T = 273 + 34 = 307 K
λm x 307 = 2898
λm = 9.44 μm
= 9440 nm
It is infrared radiation .
b )
We shall apply Stefan's law of radiation.
E = σA T⁴
E is emitted radiation by body acting as black body , A is surface area , T is absolute temperature of body
σ = 5.67 x 10⁻⁸ J / m²T⁴
Surface area of a typical man's body A = 1.9 m²
T = 273 + 34 = 307 K
Assuming human body as black body
E = 5.67 x 10⁻⁸ x 1.9 x 307⁴ J/s
= 9.57 x 10² J/s
= 957 W .
c )
Radiation absorbed
E = 5.67 x 10⁻⁸ x 1.9 x ( 273 + 20 )⁴ J/s
= 794 W .
A 16 g ball at the end of a 1.4 m string is swung in a horizontal circle. It revolves once every 1.09 s. What is the magnitude of the string's tension?
Answer and I will give you brainiliest
Answer:
6.56
Explanation:
frequency = 1/1.09 = 0.92 Hz
f = 1/(2L) × √T/m
0.92 = 1/2(1.4) × (√T/√16)
0.92 = 0.36 × (√T)/4
multiply all through by 4
3.68 = 1.44 × √T
√T = 3.68/1.44 = 2.56
T = 2.56² = 6.56
The magnitude of the string's tension as it is swung in a horizontal circle is 0.744 Newton
Given the data in the question;
Mass of the ball;[tex]m = 16g = 0.016kg[/tex]String is swung in a horizontal circle, Radius; [tex]r = 1.4m[/tex]Period of revolution; [tex]T = 1.09s[/tex]Magnitude of the string's tension; [tex]F_T = ?[/tex]First, we need to get magnitude of the centripetal acceleration:
[tex]a_c = \frac{4\pi ^2r}{T^2}[/tex]
We substitute in our given values
[tex]a_c = \frac{4\pi ^2\ *\ 1.4m}{(1.09s)^2} \\\\a_c = 46.519 m/s^2[/tex]
Now, from Newton's Second Law of Motion:
[tex]F = m\ * \ a[/tex]
Where F is the force, m is the mass of the object and a is the acceleration
We substitute into the equation to get the magnitude of the string's tension.
[tex]F = 0.016kg \ *\ 46.519m/s^2[/tex]
[tex]F = 0.744 kg.m/s^2\\\\F = 0.744 N[/tex]
Therefore, the magnitude of the string's tension as it is swung in a horizontal circle is 0.744 Newton
Learn more; https://brainly.com/question/14039108
Which of the following has the most kinetic energy?
A.
A car traveling at 80 kph.
B.
A tractor trailer traveling at 80 kph.
C.
A cheetah running at 80 kph.
D.
A notorcycle traveling at 80 kph.
Answer:
B
Explanation:
A tractor is the heaviest
(b) The efficiency of the pump which operates the fountain is 70%.
Calculate the power supplied to the pump.
Answer:
Power supplied to the pump is 980000 W or 980 KW
Note: The question is incomplete. The complete question is given below:
On a day with no wind, a fountain in Switzerland propels 30000 kg of water per minute to a height of 140 metres.
a)Calculate the power used in raising the water?
b)The efficiency of the pump which operates the fountain is 70%
calculate the power supplied to the pump?
Explanation:
Efficiency = Power output/Power input * 100%
Power output = work done/ time
where work done = mass * acceleration due to gravity (g) * height
time = 1 minute = 60 seconds
mass of water = 30000 kg, height = 140 meters, g = 9.8 m/s²
Then, work done = 30000 * 140 * 9.8 = 41160000 J
Power output then = 41160000 J / 60 s
Power output = 686000 W
The power input can then be derived from the formula of efficiency
Power input = (Power output * 100)/Efficiency
Power input = (100 * 686000) / 70
Power input = 980000 W
Therefore, power supplied to the pump is 980000 W or 980 KW
A person is standing on a level floor. His head, upper torso, arms, and hands together weigh 458 N and have a center of gravity that is 1.34 m above the floor. His upper legs weigh 120 N and have a center of gravity that is 0.766 m above the floor. Finally, his lower legs and feet together weigh 89.8 N and have a center of gravity that is 0.204 m above the floor. Relative to the floor, find the location of the center of gravity for the entire body.
Answer:
the location of the center of gravity for the entire body is 1.08 m
Explanation:
Given the data in the question;
w1 = 458 N, y1 = 1.34 m
w2 = 120 N, y2 = 0.766 m
w3 = 89.8 N, y2 = 0.204 m
The location arrangement of the body part is vertical, locate the overall centre of gravity by simply replacing the horizontal position x by the vertical position y as measured relative to the floor.
so,
[tex]Y_{centre of gravity}[/tex] = (w1y1 + w2y2 + w3y3 ) / ( w1 + w2 + w3 )
so we substitute in our values
[tex]Y_{centre of gravity}[/tex] = (458×1.34 + 120×0.766 + 89.8×0.204 ) / ( 458 + 120 + 89.8 )
[tex]Y_{centre of gravity}[/tex] = 723.9592 / 667.8
[tex]Y_{centre of gravity}[/tex] = 1.08 m
Therefore, the location of the center of gravity for the entire body is 1.08 m
A person in car slides to the right when going through a very sharp left turn on the highway. Is that law of inertia or law of acceleration?
Answer:
Inertia :)
Explanation:
A rotating paddle wheel is inserted in a closed pot of water. The stirring action of the paddle wheel heats the water. During the process, 30 kJ of heat is transferred to the water and 5 kJ is lost to the surrounding air. The paddle wheel work amounts to 500 J. Determine the final energy of the system if its initial energy is 10 kJ.
Answer:
the final energy of the system is 35.5 kJ.
Explanation:
Given;
initial energy of the system, E₁ = 10 kJ
heat transferred to the system, q₁ 30 kJ
Heat lost to the surrounding, q₂ = 5kJ
heat gained by the system, Q = q₁ - q₂ = 30 kJ - 5kJ = 25 kJ
work done on the system, W = 500 J = 0.5 kJ
Apply first law of thermodynamic,
ΔU = Q + W
where;
ΔU is change in internal energy
Q is the heat gained by the system
W is work done on the system
ΔU = 25kJ + 0.5 kJ
ΔU = 25.5 kJ
The final energy of the system is calculated as;
E₂ = E₁ + ΔU
E₂ = 10 kJ + 25.5 kJ
E₂ = 35.5 kJ.
Therefore, the final energy of the system is 35.5 kJ.
Can heating cooking oil you’ll be classified as producing a chemical change?
yes it is boiling creating bubbles that aren't their originally
Explanation:
When cooking oils are subjected to heat in the presence of air and water (from food), such as in deep-fat frying and sautéing (pan frying), they can undergo at least three chemical changes: 1) oxidation of the fatty acids, 2) polymerization of the fatty acids, and 3) breaking apart of the triglyceride molecules into free fatty acids and glycerol by hydrolysis (reaction with water from the food being cooked) (Choe and Min 2007)
Two carts collide and have a perfectly inelastic collision. Cart1 has a mass of 500 grams and
Cart2 has a mass of 600 grams. Cart1 has an initial westward velocity of 1.6 m/s and collides
with Cart2 which was initially at rest. What is was the final velocity of the two cart system (SI
units)?
Answer: look at the file
Which sentence is correct?
Answer:
pretty sure its B if it isnt im so so sorry
Explanation:
Could I please get some help on this question I don’t understand .
Answer:
12.5 m/s
Explanation:
From the question given above, the following data were obtained:
Initial velocity (u) = 0 m/s
Height (h) = 8 m
Final velocity (v) at 8 m above the lowest point =?
NOTE: Acceleration due to gravity (g) = 9.8 m/s²
The velocity of the roller coaster at 8 m above the lowest point can be obtained as follow:
v² = u² + 2gh
v² = 0² + (2 × 9.8 × 8)
v² = 0 + 156.8
v² = 156.8
Take the square root of both side
v = √156.8
v = 12.5 m/s
Therefore, the velocity of the roller coaster at 8 m above the lowest point is 12.5 m/s.
The amount of energy a substance has depends on the state of matter
the substance is in at the time.
True
or False
a virtual image is formed by
a) simple microscope b) telescope c) the ordinary camera d) a slide projector in a cinema hall
Answer: ordinary camera
Explanation:
Answer:
C.
Explanation:
Approximately where is it currently high tide on Earth? Group of answer choices wherever it is currently noon anywhere that ocean water laps upon the shore on the portion of Earth facing directly toward the Moon and on the portion of Earth facing directly away from the Moon only on the portion of the Earth facing directly toward the Moon
Answer:
Option D, only on the portion of the Earth facing directly toward the Moon
Explanation:
Tides are caused by the gravitational pull of moon. The part of earth that faces the moon experiences the highest gravitational force and hence the high tides will occur in this regions only. The regions that do not faces the moon experiences low tides. It is the gravity of moon that attracts the ocean water towards itself.
Hence, Option D is correct
Students in an introductory physics lab are performing an experiment with a parallel-plate capacitor made of two circular aluminum plates, each 20 cm in diameter, separated by 1.0 cm. How much charge can be added to each of the plates before a spark jumps between the two plates? For such flat electrodes, the field that causes a spark is at the high end of the range pre- sented in the chapter; assume a value of 3 * 106 N/C.
Answer:
Q = 0.83 μC
Explanation:
Assuming that plates are much larger than the distance between them, we can think the electric field as constant and perpendicular to the outer surface of the plates.Applying Gauss' law to a rectangular surface half inside one of the plates and half outside it, since E and A are parallel each other, and E is zero on the other three faces, we can find the following expression for the electric field created by the charge on the plate:[tex]E = \frac{Q*A}{\epsilon_{0} } (1)[/tex]
Solving for Q, replacing E by the maximum electric field that doesn't cause the dielectric strength to break (3*10⁶ N/C), we get:[tex]Q_{max} = E_{max} * \pi *\frac{d^{2}}{4} *\epsilon_{0} = 3e6N/C*\pi *\frac{(0.2m)^{2} }{4} * 8.85e-12C2/Nm2 = 0.83\mu C (2)[/tex]
What color is seen when cyan light is shown on magenta paper
Answer:
blue
You see white. What happens when you shine cyan light on a magenta shirt? You see blue.
Explanation:
give two differences between sextusl reproduction and asextual reproduction
Answer:
Sexual reproduction you need two organisms to reproduce.
Asexual is when you can multiply yourself and there is nothing different about the offspring and the parent.
How does the energy in a system of magnets change when two magnets repel and move away from each other
A light source emits light with dominant wavelengths in the range of 650 to 690 nm. what is the principle color of light emitted by the source?
Answer:
Please see below as the answer is self-explanatory.
Explanation:
The visible range extends roughly from 400 nm (violet) to 700 nm (red).Below the violet is the ultra-violet spectrum (with higher energy) and above red, we have the infra-red spectrum.The wavelengths in the range of 650 to 690 nm have red as the dominant color.Water pollution can come from the _______ of dead organic matter or animal waste in waterways.
Water pollution can come from the remains of dead organic matter or animal waste in waterways
Answer:
Water pollution can come from the remains of dead organic matter or animal waste in waterways.
it is a line that intersects a circle at exactly two points.
Secant is the answer. Please mark brainliest.
A line that intersects a circle at exactly two points is called a secant line.
hope this helped!
if a wave passes every 17.4 seconds, what is the frequency?
Answer:
to be completely honest I have no idea however I tried calculating it on a calculator and umm...
I think the frequency is...
17,229,452
but ya know I could be totally wrong so if I am sorry
flint glass materials
Answer:
Flint glass is combination of silicon dioxide (SiO2) with lead or potassium. It creates a relatively high refractive index and high degree of light dispersing power compared to other types of glass.
Explanation:
:)
Answer:Flint glass is combination of silicon dioxide (SiO2) with lead or potassium. It creates a relatively high refractive index and high degree of light dispersing power compared to other types of glass.
Explanation:
3. It takes at least 4 people to push a refrigerator up a 10-meter ramp. How many people would be needed to push the same refrigerator to the same height using a
20-meter ramp? (Assume no friction for both ramps.)
O A. at least 2 people
O B. at least 4 people
O c. at least 8 people
D. Not enough information (could be impossible).
.
Answer:
A
Explanation: Using a ramp that is twice is long (and therefore flatter) means that half as much force is needed. Force is provided by the people who push, so only half as many people would be needed.
At least 2 people would be needed to push the same refrigerator to the same height using a 20-meter ramp.
Given the following data:
Number of people = 4 people.Height A = 10 meters.Height B = 20 meters.What is a ramp?A ramp can be defined as a sloping plane or surface that is typically used to connect two (2) levels; a higher and a lower level.
In this scenario, a ramp that is twice as long as the first ramp was used to push a refrigerator up. This simply means that, half the magnitude of force provided by the 4 people pushing the refrigerator up a 10-meter ramp would be needed for the 20-meter ramp, assuming no friction for both ramps.
In conclusion, we can deduce that at least 2 people would be needed to push the same refrigerator to the same height using a 20-meter ramp.
Read more on forces here: https://brainly.com/question/931387
What energy transfer happens in many musical instruments?
Sound to kinetic
Electrical to kinetic
Kinetic to sound
Answer:
kinetic to sound
Explanation:
this is because energy is moving in the instrument and it produces sound.
why don't we draw lewis dot diagrams for nobel gases
Shine the flashlight on the liquid sheet. Did you observe evidence that light carries energy
Answer:
Think of an object you have observed ... Work with your group to gather evidence that light carries energy, then answer the questions below. Shine the flashlight on the liquid crystal sheet.
image.
A concave lens always produces a(n)
A. inverted
o
B. real
C. virtual
D. magnified
Answer:
Explanation:
Its Virtual, how would you describe the image formed by a convex mirrior? virtual upright, smaller
Could a sea breeze occur at night? Explain why or why not.
A volleyball player spiking is it kinetic or potential
Answer:
It is kinetic energy.
Explanation:
The kinetic energy of an object is the energy that it possesses due to its motion. It is defined as the work needed to accelerate the volleyball from rest to its stated velocity. Having gained this energy from the player spiking it during its acceleration, the body maintains this kinetic energy unless its speed changes.
How much work is done against gravity when lifting a 2-kg sack of groceries a distance of 2.5 meters?