If you lie on the ground at night with no cover, you get cold rather quickly. Much of this is due to energy loss by radiation. At night in a dry climate, the temperature of the sky can drop to −40∘C. If you are lying on the ground with thin clothing that provides little insulation, the surface temperature of your skin and clothes will be about 30∘C. Estimate the net rate at which you body loses energy by radiation to the night sky under these conditions. Hint: What area should we use?

Answers

Answer 1

Answer:

301.48 J/s

Explanation:

We are given;

Temperature of the sky dropping to −40∘C: T_o = -40°C = -40 + 273 = 233 K

Temperature of your skin and clothes: T = 30°C = 30 + 273 = 303 K

Body surface area of human body is around 2 m². But here only half of the body is facing the sky, Thus Area is: A = 2/2 = 1 m²

To solve this, we will use the equation for thermal heat transfer known as the Stefan bolt Mann equation.

ΔQ/Δt = εσA(T⁴ - (T_o)⁴)

Where;

ΔQ/Δt is the rate at which you body loses energy by radiation

ε is the emissivity of the human body with a value of 0.97

σ is Stefan boltzmann constant with a value of 5.67 X 10^(-8) W/m².K⁴

Thus;

ΔQ/Δt = 0.97 × 5.67 X 10^(-8) × 1(303⁴ - 233⁴)

ΔQ/Δt = 301.48 J/s


Related Questions

If a body having mass 40kg started moving initially with rest and it takes a velocity of 20m/sec in time 4 seconds. Find the value of force​

Answers

[tex]{\mathfrak{\underline{\purple{\:\:\: Given:-\:\:\:}}}} \\ \\[/tex]

[tex]\:\:\:\:\bullet\:\:\:\sf{Mass \ of \ the \ body \ (m) = 40 \ kg}[/tex]

[tex]\:\:\:\:\bullet\:\:\:\sf{Final \ velocity \ of \ the \ body \ (v) = 20 \ m/s}[/tex]

[tex]\:\:\:\:\bullet\:\:\:\sf{Initial \ velocity \ of \ the \ body \ (u) = 0}[/tex]

[tex]\\[/tex]

[tex]{\mathfrak{\underline{\purple{\:\:\:To \:Find:-\:\:\:}}}} \\ \\[/tex]

[tex]\:\:\:\:\bullet\:\:\:\sf{Force \ exerted \ by \ the \ body \ ( F)}[/tex]

[tex]\\[/tex]

[tex]{\mathfrak{\underline{\purple{\:\:\: Solution:-\:\:\:}}}} \\ \\[/tex]

Using 1st equation of motion

[tex]\\[/tex]

[tex]\dashrightarrow\:\: \sf{v = u + at}[/tex]

[tex]\\[/tex]

[tex]\dashrightarrow\:\: \sf{20 = 0 + a(4)}[/tex]

[tex]\\[/tex]

[tex]\dashrightarrow\:\: \sf{20 = 4a}[/tex]

[tex]\\[/tex]

[tex]\dashrightarrow\:\: \sf{\dfrac{\cancel{20}}{\cancel{4}} = a}[/tex]

[tex]\\[/tex]

[tex]\dashrightarrow\:\: \sf{a = 5}[/tex]

[tex]\\[/tex]

Now, Finding the force exerted

[tex]\\[/tex]

[tex]\dashrightarrow\:\: \sf{F = ma}[/tex]

[tex]\\[/tex]

[tex]\dashrightarrow\:\: \sf{F = 40 \times 5}[/tex]

[tex]\\[/tex]

[tex]\dashrightarrow\:\: \sf{F = 200 \ N}[/tex]

[tex]\\[/tex]

Hence, [tex]\\[/tex]

[tex]\:\:\:\:\star\:\:\:\sf{The \ force \ exerted \ by \ the \ body \ is \ 200N}[/tex]

Object A has a mass of 2 kg; object B’s mass is 10 kg. If object B is at rest and object A runs into it at low speed, object B:


A. Will move off at high speed.
B. Cannot move off with high speed.
C. Will loose speed in the collision.
D. Will remain at rest.

Answers

D will remain at rest because it has a less mass and is moving slowly so it won’t effect the position of object b

Answer:

Cannot move off with high speed

Explanation:

Just did it

which of the following is true of phototsythesis but not of cellular respiration.

A- Photosynthesis releases oxygen gas as a product
B- Photosynthesis occurs in all organisms
C- Photo synthesis is a process in which glucose i broken down
D- Photosynthesis requires glucose as a reactant

Answers

Answer:

B. Photosynthesis occurs in all organisms

Hope this helps!! :)

When liquid water gets into cracks of rock and freezes, it __ and ___.

Answers

It expands and pushes the crack further aprt

Which of the following statements are true of cancer types? Check all that apply. --
- Cancer is named according to the color the cells turn.
- Skin cancer is considered a very common type of cancer.
- Cancer is often named according to what body type it affects.
- Skin cancer is the least common type of cancer.

Answers

the answer is cancer is often named according to what body type it affects

Answer:

B,C

Explanation:

skin cancer is considered a very common type of cancer. Cancer is often named accordingly to a body type it affects.

The voltage provided by the battery of a circuit was 12 V, if the total
resistance in the circuit was 6 ohms, calculate the total current present.
options:
72 A
2A
0.5 A
7.2 A​

Answers

Answer:

2 Amps

which agrees with the second option in the list of answers

Explanation:

Use Ohm's law:

V = R * I

which with the information given to us becomes:

12 = 6 * I

then solving for I we get:

I = 12 V / 6 Ω = 2 Amps

Two ice-skaters are skating in circles on a frozen pond. Maria is making large circles with a radius of 12 m and skating 4.5 m/s. Her friend, Samantha, is making smaller circles with a radius of 6 m but is not skating as quickly, going only 3.8 m/s. ii. How could each skater increase her centripetal acceleration without changing the size of her path? Explain your reasoning.

Answers

Answer:

v_maria > 4.5 m/s

v_samantha > 3.8 m/s

Explanation:

Formula for centripetal acceleration is;

a_c = v²/r

Where;

v is speed

r is radius

For Maria;

r = 12 m

v = 4.5 m/s

Thus;

a_c = 4.5²/12

a_c = 1.6875 m/s²

For Samantha;

r = 6

v = 3.8 m/s

Thus;

a_c = 3.8²/6

a_c = 2.41 m/s²

We want to find how could each skater increase her centripetal acceleration without changing the size of her path.

From the centripetal acceleration formula, since the size of path can't be changed it means the radius can't be changed and so the only thing that can now increase the centripetal acceleration is when the speed increases.

Thus;

For Maria, she has to move with a faster speed. Thus: v_maria > 4.5 m/s

For Samantha, she also has to move with a faster speed. Thus; v_samantha > 3.8 m/s

A string with mass per unit length of 0.003 kg/m is plucked with an amplitude of 2 cm. The string is 30 cm long, and under a tension of 30 newtons. What are the frequencies of the first 5 harmonics?

Answers

Answer:

First harmonics = 333.33N

Second harmonics = 500.01N

Third harmonics = 666.68N

Fourth harmonics = 833.35N

Fifth harmonics = 1000.02N

Explanation:

The formula for calculating the fundamental frequency in string is expressed as;

[tex]F_0 = \frac{1}{2L}\sqrt{\frac{T}{m} }[/tex] where;

L is the length of the string = 30cm = 0.3m

T is the tension in the string = 30N

m is the mass per unit length of the string = 0.003kg/m

Get the fundamental frequency first by substituting the given values into the formula;

[tex]F_0 = \frac{1}{2(0.3)}\sqrt{\frac{30}{0.003} }\\F_0 = \frac{1}{0.6}\sqrt{10,000}}\\F_0 = \frac{1}{0.6} * 100\\[/tex]

F0 = 166.67N

Harmonics are the integral multiples of the fundamental frequency.

First harmonics F1 = 2F0 = 2(166.67) = 333.33N

Second harmonics F2 = 3F0 = 3(166.67) = 500.01N

Third harmonics F3 = 4F0 = 4(166.67) = 666.68N

Fourth harmonics F4 = 5f0 = 5(166.67) = 833.35N

Fifth harmonics F5 = 6f0 = 6(166.67) = 1000.02N

what is the need of force in our life​

Answers

Answer:

A force is a push or a pull and it affects our daily lives because without force,people would not be able to open and close stuff or lift up our arms or legs .....or anything, for that matter.

Explanation:

brainly

Without forces, we couldn’t live. If you push or pull on an object a force is being applied. Forces can also make objects stay
where they are

What is the approximate distance from the sun to the astroid belt?

Answers

Answer:

The asteroid belt lies between 2.2 and 3.2 astronomical units (AU) from our sun. ( i looked this up because nobody of the top of their head knows this)

Explanation:

A fluid of density rho = 900 kg/m3 flows along a pipe of constant diameter from point A to point B. Gauge pressure at point A is equal to zero, and absolute pressure at point B is 30% lower than pressure at point A. What is the height difference, Δh, between points A and B?
a. Δh = 8.09 m with point A above point B.
b. Δh = 344 m with point B above point A.
c. Δh = 303 m with point B above point A.
d. Δh = 3.44 m with point A above point B.

Answers

The height difference between points A and B is : ( B ) Δh = 3.44 m with point B above point A.

Given data :

fluid density = 900 kg/m³

Diameter of pipe = constant

Gauge pressure at Point A = 0

Gauge pressure at point B = 30% lower

Determine the height difference between points A and B

first step : determine absolute pressure

Pa (absolute pressure )= gauge pressure + atmospheric pressure

                                      = 0 + patm

Therefore : Pa = Patm

Also;

Pressure at point B ( Pb ) = Pa - 30%Pa

                                          = 0.7 Patm

Hence ; Pa - Pb = 0.3 Patm ----- ( 1 )

Final step : Determine the height difference

we will apply the formula below from equation ( 1 )

p *g * Δh = 0.3 * 1.013 * 10⁵      ( note : Patm = 1.013 * 10⁵ )

900 * 9.81 * Δh = 0.3 * 1.013 * 10⁵

therefore :

Δh = ( 0.3 * 1.013 * 10⁵ ) / ( 900 * 9.81 )

     = 3.44 m

Hence we can conclude that The height difference between points A and B is Δh = 3.44 m with point B above point A.

Learn more about height difference in fluids : https://brainly.com/question/17200230

Describe how radiant energy, light energy, and solar energy are related. ( Please ❤️ )

Answers

Answer:

L’énergie solaire récolte l’énergie radiante portée par la lumière de notre soleil en la convertissant en électricité.Biomasse des plantes. Les plantes sont capables d’exploiter et d’utiliser l’énergie lumineuse dans un processus appelé photosynthèse.

Answer:

Radiant energy, light energy, and solar energy are related because The Sun produces a lot of radiant energy that is transmitted to Earth as light. Plants convert the electromagnetic energy in sunlight into chemical energy for their food, through a process called photosynthesis. Waves of radiant electromagnetic energy can be visible or invisible.

Explanation:

A cannonball is fired at a 45.0° angle and an initial velocity of 670 m/s. Assume no air resistance. How high did the cannonball travel?
9935 m
11454 m
754 m
13200 m

Answers

13200 m , hope this help

Paco pulls a 67 kg crate with 738 N and of force across a frictionless floor 9.0 M how much work does he do in moving the crate

Answers

Answer:

W = 6642 J

Explanation:

Given that,

Mass of a crate, m = 67 kg

Force with which the crate is pulled, F = 738 N

It is moved 9 m across a frictionless floor

We need to find the work done in moving the crate. Let the work done is W. It is given by :

W = F d

W = 738 N × 9 m

= 6642 J

So, the work done is 6642 J.

Changing which factor would NOT have an influence on the kinetic energy of a moving van loaded with 100 kg bags mulch of with a total mass of 1,500 kg. The vehicle is traveling across an open parking lot at a speed of 5 m/s.
Question 8 options:


A: direction the moving van is going across the parking lot.


B: increasing the rate of speed without altering the mass of the vehicle or its contents.


C: emptying the moving van one bag at a time at a constant rate.


D: adding more contents (increasing the overall mass) to the van while the van is in motion traveling 5 m

Answers

Answer:

A. The direction

Explanation:

I did the test lol

Answer:

A

Explanation:

i took the test

When weather predictions are incorrect what is the most likely cause
A: measurements of the initial conditions may have been very in accurate

B: small differences in models can lead to large differences in complex systems

C: The person predicting the weather may have had a bias

D: The elevation of different landforms I have been significantly in accurate

Answers

Answer:small differences in models can lead to large differences in complex systems

Explanation:   this is the  most accurate phrase  

Introduction to Simple Machines
This activity will help you meet this educational goal:
You will compare and contrast information from a video with information from a text.

Directions
Read the instructions for this self-checked activity. Type in your response to each question, and check your answers. At the end of the activity, write a brief evaluation of your work.
Activity
Watch this video and then answer the following questions based on what you learned.

Part A
How does a bicycle make work easier?





Part B
Which two examples of levers are mentioned in the video?








The picture shows a bicycle’s pedals. Look at the shaft that the pedals are attached to. Do you think the shaft is a lever? Why or why not?

Answers

Answer:

word for word answers!

Explanation:

1) Part A: By pedaling a bicycle lightly, the rider can go a long way

2) Part B: The two examples mentioned in the video are the handlebars and the brakes

3) Yes, it’s a type of lever because the two pedals rotate around a fixed point

on the moon which object would fall with the same acceleration?

Answers

Answer:

Since there is no air resistance on the Moon, all objects would be in free fall at 1.6 m/s2. This means that they would all hit the ground at the same time if released simultaneously from the same height, but at a slower speed compared to objects free falling in a vacuum on Earth.

Explanation:

The glowing dot represents the transmission of a nerve impulse along the nerves that make up the neural pathway. A nerve impulse is an electrical signal that travels from one nerve cell to another.

Which part of the brain processes this signal?

Answers

Answer:

The answer is "Cerebral Cortex"

Explanation:

The neurotransmitter diffuses across the short distance of the synapse and ties to a receptor protein of the objective neuron. At the point when the sub-atomic sign ties to the receptor, the cell film of the objective neuron changes its electrical state and another evaluated expected starts. On the off chance that that evaluated potential is sufficiently able to arrive at limit, the subsequent neuron produces an activity potential at its axon hillock. The objective of this neuron is another neuron in the thalamus of the mind, the piece of the CNS that goes about as a transfer for tactile data.

At another neurotransmitter, synapse is delivered and ties to its receptor. The thalamus at that point sends the sensory information to the cerebral cortex, the furthest layer of dark issue in the brain, where cognizant view of that water temperature starts.

A region of the cortex is particular for imparting signs down to the spinal cord for development. The upper engine neuron is in this area, called the precentral gyrus of the frontal cortex, which has an axon that broadens right down the spinal cord. At the degree of the spinal cord at which this axon makes a neurotransmitter, a reviewed potential happens in the cell membrane of a lower engine neuron.

A solid CUBE has a side of 4cm and is 192 grams in mass. What is the density?

Answers

Answer:

3g/cm³

Explanation:

Given parameters:

Length of the side  = 4cm;

  Volume of the cube  = L³  = 4³  = 64cm³

Mass of the cube  = 192g

Unknown:

Density = ?

Solution:

The density of a body is its mass per unit volume;

 Density = [tex]\frac{mass}{volume}[/tex]  

Insert parameters and solve;

Density  = [tex]\frac{192}{64}[/tex]  = 3g/cm³

Students had two batteries and two different resistors. During four trials, they build four different circuits and measure the circuit’s current in Amps according to the following table.



Trial Number

Voltage (V)

Resistance (Ω)

Current (A)

1

1.5

200


2

1.5

100


3

3.0

200


4

3.0

100




For which trial would the students measure the smallest current in the circuit? (AKS 10a)



A.
Trial 1

B.
Trial 2

C.
Trial 3

D.
Trial 4

Answers

Answer:

bhi jo bhi of gp oh oh gi IG 7u to uff do if goo td to yd do FP ae rt 7g hi pic vo icon

Explanation:

bh hi h bhi vc di oh x At jb jo iv hp of di of dr hi o hc x gh ki vc hi jo

A 100 kg man stands still. Gravity pushes on him with an acceleration of 9.8 m/s^2. What it the force the man feels from gravity? *
0 N
98 N
90 N
980 N

Answers

Answer:

980 N

Explanation:

The force acting on an object given it's mass and acceleration can be found by using the formula

force = mass × acceleration

From the question we have

force = 100 × 9.8

We have the final answer as

980 N

Hope this helps you

Pretty simple physics :) will give brainliest
pls dont just use me for points

Answers

Answer:

meter per second(m/s)

Explanation:

What is the minimum work done by the heart to pump 130 g of blood from a person's foot to his heart 1.5 m away?
A. 0J.B. 4.7J.C. .47J.D. 4700J.

Answers

Answer:

The minimum work done by the heart is 1.911 J

Explanation:

Given;

mass of the blood, m = 130 g = 0.13 kg

height the blood is pumped, h = 1.5 m

Apply work energy theorem, the gravitational potential energy of the height in which the blood is pumped to, is equal to the work done in pumping the blood form the foot to the heart.

E = mgh = W

where;

g is acceleration due to gravity = 9.8 m/s²

W = (0.13)(9.8)(1.5)

W = 1.911 J

Thus, the minimum work done by the heart is 1.911 J

You throw a baseball (mass 0.145 kg) vertically upward. It leaves your hand moving at 12.0 m/s. Air resistance can be neglected.
A. At what height above your hand does the ball have half as much upward velocity?
B. At what height above your hand does the ball have half as much kinetic energy as when it left your hand?

Answers

Answer:

Explanation:

A ) initial velocity u = 12 m /s

final velocity v = 6 m /s

height = h

acceleration = - g = - 9.8 m /s²

v² = u² - 2gh

6² = 12² - 2 x 9.8 x h

h = 5.51 m

B )

Let the final velocity when energy becomes half be V at height H

kinetic energy at height h = 1/2 m V²

Given ,

.5 x 1 / 2 m x 12² = 1/2 m x V²

V² = 12² / 2

V = 8.486 m /s

V² = u² - 2 gH

8.486² = 12² - 2 x 9.8 x H

H = 3.67 m .  

What is the initial vertical velocity of the ball?
A.
0 m/s


B.
9.81 m/s


C.
20.0 m/s


D.
60.0 m/s

Answers

I think that it is B hope this helps

find the vector parallel to the resultant of the vector A=i +4j-2k and B=3i-5j+k​

Answers

Answer:

2008

Explanation:

2000+3+5======2008

Answer:

[tex]8\hat i-2\hat j-2\hat k[/tex]

Explanation:

Vectors in 3D

Given a vector

[tex]\vec P = P_x\hat i+P_y\hat j+P_z\hat k[/tex]

A vector [tex]\vec Q[/tex] parallel to [tex]\vec P[/tex] is:

[tex]\vec Q = k.\vec P[/tex]

Where k is any constant different from zero.

We are given the vectors:

[tex]\vec A = \hat i+4\hat j-2\hat k[/tex]

[tex]\vec B = 3\hat i-5\hat j+\hat k[/tex]

It's not specified what the 'resultant' is about, we'll assume it's the result of the sum of both vectors, thus:

[tex]\vec A +\vec B = \hat i+4\hat j-2\hat k + 3\hat i-5\hat j+\hat k[/tex]

Adding each component separately:

[tex]\vec A +\vec B = 4\hat i-\hat j-\hat k[/tex]

To find a vector parallel to the sum, we select k=2:

[tex]2(\vec A +\vec B )= 8\hat i-2\hat j-2\hat k[/tex]

Thus one vector parallel to the resultant of both vectors is:

[tex]\mathbf{8\hat i-2\hat j-2\hat k}[/tex]

Under state law, what is the blood-alcohol limit for legally operating a motor vehicle?

Answers

Answer:

HOPE IT HELPS.....

Explanation:

The legal standard for drunkenness across the United States ranges from 0.10 to 0.08. If a person's BAC measures 0.08, it means that there are 0.08 grams (i.e., 80 mg) of alcohol per 100 ml of blood. The American Medical Association says that a person can become impaired when the blood alcohol level hits 0.05.

Answer: 0.08

Driving While Intoxicated or Impaired is Illegal

Under Michigan law, it is illegal to drive: While intoxicated, or impaired, by alcohol, controlled substance, or other intoxicating substance. With a bodily alcohol content of 0.08 or more. (This crime is one of the driving while intoxicated offenses.)

Hope this helps... Stay safe and have a Merry Christmas!!!!!!!! :D

A scientist who wants to study the affects of fertilizer on plants sets up an experiment. Plant A gets no fertilizer, Plant B gets 5 milligrams of fertilizer, and Plant C gets 10 milligrams of fertilizer. Which plant is the control group in this experiment?

Answers

Answer: Plant A

Explanation: The control group is participants who do not receive the experimental treatment.

_____ are group of tissue working together to perform a certain job.

Answers

Answer:

organ

Explanation:

Answer:

an organ

Explanation:

cell -> tissue -> organ -> organ system -> organism

Other Questions
Drag each tile to the correct box. Match each group discussion strategy with a description of how to use it. Think carefully about what you want Work collaboratively with group to say and say what you mean. Members and ask thoughtful questions Use exact language and provide examples to support your points. Make eye contact with group members and ask thoughtful questions.. Be clear. arrowRight Listen carefully. arrowRight Speak deliberately. arrowRight whiches goes in the blanks What action by the leaders of the French Revolution demonstrates that they were influenced by Enlightenment ideas? GIVIING BRAINLIST "Ah, distinctly I remember, it was in the bleak December,And each separate dying ember wrought its ghost upon the floor."With these lines, the narrator is saying thatA) The fire is burning out.B) The fire has transformed into ghosts.C) The fire is growing supernaturally strong.D) The fire is ghostly in substance, even if non-ghostlyin appearance . The number of pizzas is in a proportional relationship to the weight of the shredded cheese toppings. When shredded, a 50-lb block of cheese is enough to make 150 large pizzas. Find the constant of proportionality. Use pencil and paper. Explain how you can use a constant of proportionality to find how much cheese is on one slice of pizza if there are 8 slices per pizza. The collapse of the magnetic field inside the ignition coil happens as aresult of the interruption of current to the: How would a sonar enable an underwater vessel to move through the ocean depths? Enter the value of p so that the expression 3(4+n) is equivalent to 3(n+p). HELP PLEASE!! 30 POINTS!!!!! NO FAKE ANSWER PLEASE!!in "The Thread That Runs So True"What are four things Stuart reveals about his personality through some actions, thoughts, or speech? How would Henry Watson's narrative have been used by abolitionists? PLZ HELP (30 POINTS)Which of the following is a direct benefit of using agriscience to optimize land use for animal grazing? Reducing soil degradation Inventing new fertilizers Updating irrigation Increasing climate change Find the slope. Explain what the slope and y-intercept means for the situation. Be sure to use your labels when explaining the real-life situation. 2. According to the Constitution, the requirement for a judicial branch is satisfied by:A. the Supreme Court, the district courts, and the circuit courtsB. the circuit courts alone C. the district courts aloneD. the Supreme Court alone 20+ pts and brainliest!!!! How did the Atlantic Slave Trade contribute to a racist ideology that continues today? Marigold Corp. constructed a building at a cost of $30600000. Weighted-average accumulated expenditures were $13000000, actual interest was $1300000, and avoidable interest was $604000. If the salvage value is $2400000, and the useful life is 40 years, depreciation expense for the first full year using the straight-line method is who promoted conservative medical practices?A) dark agesB) egyptians C) greeksD) hindusE) babyloniansF) chinese Mr. Smith earns $375 per week as a salary plus he earns a 4% commission. If his total sales were $4,200, how much will he earn this week? Find the area of the shaded region308 centimeters squared284 centimeters squared272 centimeters squared548 centimeters squared With whom does Peter have the most conflict and why?Margot, because she hardly talks to Peter.Anne, because she is always trying to pet his cat and writing in her journal.Dussel, because he says unkind things and calls his mother silly.Miep, because she brings Peter the wrong type of books. How do I find the measurement indicated in these problems. An ideal frictionless machine: O has very little friction O has no friction does not require work input PLEASE HELPP MEEE