Answer:
A. Net amount of heat radiated = 109.2W
B. Person's basal energy = 136.5
Explanation:
Part A:
Area of person, A = 1.90 m^2
Temperature of person , T = 31 C
T = 304 K
Temperature of surroundings , To = 19 C
To = 282 K
Now, net amount of heat radiated = e*A*sigma *(T^4 - To^4)
Net amount of heat radiated = 1 * 1.8 * 5.6703 *10^-8 *(304^4 - 294^4)
Net amount of heat radiated = 109.2 W
The net amount of heat radiated is 109.2 W
Part B:
Person's basal energy = net amount of heat radiated /(0.80)
Person's basal energy = 109.2/0.80
Person's basal energy = 136.5 W
Person's basal energy is 136.5 W
a brick of mass 0.8 kg is accidentally dropped from a high scaffolding. it reaches the ground with a kinetic energy of 240 J. How high is scaffolding ?(Take acceleration due to gravity g be 10 m s-¹)
Answer:
30 m
General Formulas and Concepts:
Energy
Gravitational Potential Energy: [tex]\displaystyle U_g = mgh[/tex]
m is mass (in kg)g is gravityh is height (in m)Kinetic Energy: [tex]\displaystyle KE = \frac{1}{2}mv^2[/tex]
m is mass (in kg)v is velocity (in m/s²)Law of Conservation of Energy
Explanation:
Step 1: Define
Identify variables
[Given] m = 0.8 kg
[Given] g = 10 m/s²
[Given] U = 240 J
[Solve] h
Step 2: Solve for h
[LCE] Substitute in variables [Gravitational Potential Energy]: (0.8 kg)(10 m/s²)h = 240 JMultiply: (8 kg · m/s²)h = 240 JIsolate h [Cancel out units]: h = 30 mA solid aluminum sphere of radius R has moment of
inertia I about an axis through its center. What is the
moment of inertia about a central axis of a solid
aluminum sphere of radius 2R?
1. 21
2. 41
3. 87
4. 161
5. 321
Answer:
5. 32I
Explanation:
The moment of inertia of a solid sphere about its central axis is given by
I = [tex]\frac{2}{5} MR^2[/tex] ------------------(i)
Where;
M = mass of the sphere
R = radius of the sphere.
From the question;
Case 1: The aluminum sphere has a radius R and moment of inertia I.
This means that we can substitute these values of R and I into equation (i) and get;
I = [tex]\frac{2}{5} MR^2[/tex] --------------(ii)
M is the mass of the aluminum sphere and is given by;
M = pV
Where;
p = density of aluminum
V = Volume of the sphere = [tex]\frac{4}{3} \pi R^3[/tex]
=> M = p([tex]\frac{4}{3} \pi R^3[/tex]) --------------------(*)
Case 2: An aluminum sphere with a radius of 2R instead.
Let the moment of inertia in this case be I' and mass be M'
Substituting R = 2R, M = M' and I = I' into equation (i) gives
I' = [tex]\frac{2}{5} M'(2R)^2[/tex] ------------------(iii)
Where;
M' = pV'
p = density of aluminum
V' = volume of the sphere = [tex]\frac{4}{3} \pi (2R)^3[/tex]
=> M' = p([tex]\frac{4}{3} \pi (2R)^3[/tex])
Rewriting gives;
M' = p([tex]\frac{4}{3} \pi (2)^3(R)^3[/tex])
M' = p([tex]\frac{4}{3} \pi8(R)^3[/tex])
M' = 8p([tex]\frac{4}{3} \pi R^3[/tex])
From equation (*), this can be written as
M' = 8M
Now substitute all necessary values into equation (ii)
I' = [tex]\frac{2}{5} M'(2R)^2[/tex]
I' = [tex]\frac{2}{5} (8M)(2R)^2[/tex]
I' = [tex]\frac{2}{5} (8M)(2)^2(R)^2[/tex]
I' = [tex]\frac{2}{5} (8M)(4)(R)^2[/tex]
I' = [tex]\frac{2}{5} (32M)(R)^2[/tex]
I' = [tex]32[\frac{2}{5}MR^2][/tex]
Comparing with equation (ii)
I' = [tex]32[I][/tex]
Therefore, the moment of inertia about a central axis of a solid
aluminum sphere of radius 2R is 32I
cho hệ cơ học như hình vẽ hai đầu dây buộc hai vật có khối lượng tương ứng là m1=2kg và m2>m1 lấy g=10m/s sau 1s kể từ lúc bắt đầu chuyển dộng hệ vật đi được 50 cm tính m2 và sức căng của dây
xin lỗi không có sơ đồ vui lòng cho biết sơ đồ

HELP PLSS I CANT FAIL!!!
Elements from Period 3 of the periodic table are highlighted. Which element
is a metalloid?
A. Sodium
B. Argon
C. Sulfur
D. Silicon
Answer:
Explanation:
Look at the color scheme. That will help you a lot.
The metals are Na Mg and Al. They are colored Blue.
The Non metals are colored yellow.
Seven of the eight entries are taken up by yellow or blue. There is only 1 element left over and that is Si. So it must the metalloid. It has properties of the both the metals and the non metals.
Answer: silicon
Explanation:
The equation of damped oscillations is given in the form x=0.05e^-0.25sin½πt (m). Find the velocity of an oscillating point at the moments of time: 0, T, 2T, 3T and 4T.
Explanation:
Finding the (maximum) respective prime powers would yield the answer. Also we need not ... Is perfectly divisible by 720^n? ... So we can say that for any positive value of n it not divisible.
The idea of a field was needed for which reason?
A. There was no way to calculate forces.
B. Forces were exerted without physical contact.
C. There was no way to know the direction of forces.
D. Forces affect only certain things.
Answer:
i believe b
Explanation:
for example, gravity works without directly contacting objects so a field helps visualize how gravity objects without physical interaction
Answer:
Explanation:
giâir
Two
cars, A and B , are travelling in the same
direction
although
Car B is 186 metres behind A. The
speed car B is 24.4 m/s and the speed of car A is 18.6 m/ s. How much time does it take for car B to catch up with car A?
Answer:
SA = 18.6 * t + 186 total distance traveled by A in time t
SB = 24.4 t total distance car B must travel to catch car A
SA - SB = 0 = 18.6 t + 186 = 24.4 t
(24.4 - 18.6) t = 186
t = 186 m / 5.8 m/s = 32 s
Check 18.6 * 32 + 186 = 781 m
24.4 * 32 = 781 m
A continuous succession of sinusoidal wave pulses are produced at one end of a very long string and travel along the length of the string. The wave has frequency 70.0 Hz, amplitude 5.00 mm, and wavelength 0.600 m. (a) How long does it take the wave to travel a distance of 8.00 m along the length of the string
Answer:
The time taken by the wave to travel 8 m is 0.19 s .
Explanation:
frequency, f = 70 Hz
Amplitude, A = 5 mm
Wavelength = 0.6 m
The wave speed is given by
wave speed, v = frequency x wavelength
v = 70 x 0.6
v = 42 m/s
Distance, d = 8 m
Let the time taken is t.
So, [tex]t =\frac{d}{v}\\\\t =\frac{8}{42}\\\\t = 0.19 s[/tex]
Có bao nhiêu đặc trưng sinh lý của âm
Answer:
Ba đặc trưng sinh lí của âm là độ cao, độ to và âm sắc.
Explanation:
difference between resistor or resistance
Answer:
Resistance is the property of a conductor, which determines the quantity of current that passes through it when a potential difference is applied across it. A resistor is a electrical componet with a predetermined electrical resistance, like 1 ohm, 10 ohms 100 ohms 10000 ohms etc.
I hoped I helped you. Please mark my answer as brainliest answer.
Assuming the earth is a uniform sphere of mass M and radius R, show that the acceleration of fall at the earth's surface is given by g = Gm/R2 . What is the acceleration of a satellite moving in a circular orbit round the earth of radius 2R
Explanation:
The weight of an object on the surface of the earth is equal to the gravitational force exerted by the earth on the object.
[tex]W=F_G[/tex]
[tex]mg = G \dfrac{mM}{R^2}[/tex]
which gives us an expression for the acceleration due to gravity g as
[tex]g = G\dfrac{M}{R^2}[/tex]
At a height h = R, the radius of a satellite's orbit is 2R. Then the acceleration due to gravity [tex]g_h[/tex] at this height is
[tex]mg_h = G \dfrac{mM}{(2R)^2}= G \dfrac{mM}{4R^2}[/tex]
Simplifying this, we get
[tex]g_h= G \dfrac{M}{4R^2} = \dfrac{1}{4} \left(G \dfrac{M}{R^2} \right) = \dfrac{1}{4}g[/tex]
how does the property of being polar benefit the ability of organic compounds to function in the body.
Explanation:
Organic compounds essential to human functioning include carbohydrates, lipids, proteins, and nucleotides. These compounds are said to be organic because they contain both carbon and hydrogen. ... Carbohydrate compounds provide essential body fuel.
Under which conditions would a nucleus be least likely to undergo radioactive decay? A. When the strong nuclear forces are less than the electrostatic forces of repulsion
B. When the strong nuclear forces are greater than the electrostatic forces of repulsion
C. When the strong nuclear forces are less than the electrostatic forces of attraction
D. When the strong nuclear forces are greater than the electrostatic forces of attraction
Answer:
b is the correct answer i believe
Explanation:
the strong nuclear force encourages particles to come together so that they can nuetralize, a process the opposite of the electrostatic force of repulsion. This lets the atom stay intact because if the repulsion was more than the nuclear forces strength the atom would lose electrons and slowly decay
What must a plant need to produce 4 molecules of sugar?
What must a plant need to produce 4 molecules of sugar?
Answer:
To produce a single sugar molecule a plant must use a molecule of water (H2O) and carbon dioxide (CO2) and sunlight. To get 4 molecules, you simple use 4 molecules of water and 4 molecules of carbon dioxide
When a Frisbee is flying horizontally through the air, the speed of the air flowing over the Frisbee's top is
Group of answer choices.
A. higher than the speed of the air beneath it and the pressure on top of the Frisbee is greater than the pressure beneath it.
B. lower than the speed of the air beneath it and the pressure on top of the Frisbee is less than the pressure beneath it.
C. lower than the speed of the air beneath it and the pressure on top of the Frisbee is greater than the pressure beneath it.
D. higher than the speed of the air beneath it and the pressure on top of the Frisbee is less than the pressure beneath it.
Answer:
D. higher than the speed of the air beneath it and the pressure on top of the Frisbee is less than the pressure beneath it.
Explanation:
Newton's Second Law of Motion states that the acceleration of a physical object is directly proportional to the net force acting on the physical object and inversely proportional to its mass.
Mathematically, it is given by the formula;
[tex] Acceleration = \frac {Net \; force}{mass} [/tex]
When a frisbee flies horizontally through the air, it experiences air above and beneath it. Also, there is a pressure acting on both on top and below the frisbee.
Typically, the air flowing over the top of the frisbee has a speed that is higher than the speed of the air beneath it.
Furthermore, the frisbee is able to remain in flight because the pressure on top of the frisbee is less than the pressure beneath it.
A 2.80 kg mass is dropped from a
height of 4.50 m. Find its potential
energy (PE) when it is 3.00 m
above the ground.
Answer:
PE = 82.32J
Explanation:
PE = m*g*h
PE = 2.80kg*9.8m/s²*3m
PE = 82.32J
At a playground, Maryam a 3-year old girl and Zahirah a 6-year old girl are playing with the swings. Maryam is sitting while Zahirah is standing on the swing. Both of them were given the same push by their mother. Choose the CORRECT statements:
A. Maryam is swinging faster than Zahirah.
B. Zahirah is swinging faster than Maryam.
C. Both swings at the same pace.
D. Maryam is swinging faster since she is younger.
E. Zahirah is swing faster since she is older.
Answer:
both swings at the same place
Explanation:
because there mother is giving same amount of force to both.
Estimate the force a person must exert on a massless string attached to a 0.15 kg ball to make the ball revolve in horizontal circle of radius 0.6 m. The ball makes 2 revolutions per second.
Answer:
[tex]F = 14.2 N[/tex]
Explanation:
From the question we are told that:
Mass [tex]m=0.15kg[/tex]
Radius [tex]r=0.6[/tex]
Angular Velocity [tex]\omega=2rev/s[/tex]
[tex]\omega= =2x2 \pi rad/s=>4 \pi rad/s[/tex]
Generally the equation for Force applied is mathematically given by
[tex]F =mrw2[/tex]
[tex]F=0.15*0.6* (4*x3.14^)2[/tex]
[tex]F = 14.2 N[/tex]
what was the significance of jumping a.keep the snake b.keep feet cleans c.avoid the hot water d.avoid the Bumbo stick
Answer:
D I think I’m not for sure
Explanation:
Topic: Physical and Chemical Changes
Subject: Science
Grade: 5th
Question: Why am I growing?
(Please give this answer related to Physical and Chemical Changes.
Answer: Why am I growing is a chemical change.
Explanation:
Changes that can be reversed and does not affect the composition of a substance are called physical changes.
For example, change in state of a substance like ice converting into water is a physical change.
Changes that cannot be reversed and affect the chemical composition of a substance are called chemical changes.
For example, a child growing is an irreversible change and hence, it is a chemical change.
Thus, we can conclude that why am I growing is a chemical change.
PAY ATTENTION MY QUESTION ASK FOR RADIATION!!!
You sit with friends around a campfire, roasting marshmallows. Which
transfer of thermal energy involved in this system is an example of radiation
Answer:
The answer is c
Thermal energy moves within the air from the flames to the marshmallow.
Explanation:
Hope it helps
You sit with friends around a campfire, roasting marshmallows. then the transfer of thermal energy involved in this system is an example of radiation Thermal energy moves within the air from the flames to the marshmallow. Hence option C is correct.
What is thermal Energy ?In physics and engineering, the phrase "thermal energy" is thrown around in a lot of different situations. It can relate to a variety of distinct physical notions. Included in this are the internal energy, or enthalpy, of a body of matter and radiation; heat, which is a form of energy transfer (as is thermodynamic work); and the characteristic energy of a degree of freedom in a system described in terms of its microscopic particulate constituents (where T denotes temperature and k denotes the Boltzmann constant.
Hence option C is correct.
To know more about Energy :
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A 25N[L] force acts on a 1kg object that is already travelling at 10m/s[R]. The force acts for t=2s. What is its final speed? *
A) 25m/s
B) 25m/s/s
C) 40m/s[R]
D) 40m/s[L]
show your full work please
Answer:
C) 40m/s [R]
Explanation:
Given the following data;
Force = 25 N [L]
Mass = 1 kg
Initial velocity = 0 m/s
Velocity = 10 m/s [R]
Time = 2 seconds
To find the final velocity;
First of all, we would determine the acceleration of the object.
Force = mass * acceleration
25 = 1 * acceleration
Acceleration = 25/1
Acceleration = 25 m/s²
Next, we would determine the final velocity by using the first equation of motion;
[tex] V = U + at[/tex]
Where;
V is the final velocity.
U is the initial velocity.
a is the acceleration.
t is the time measured in seconds.
Substituting into the formula, we have;
[tex] V = 0 + 25*2[/tex]
[tex] V = 0 + 50 [/tex]
V = 50 m/s
Final velocity = 50 - 10
Final velocity = 40 m/s [R]
Two uncharged metal spheres, spaced 25.0 cm apart, have a capacitance of 26.0 pF. How much work would it take to move 12.0 nC of charge from one sphere to the other? Answer in Joules.
Answer:
Use 2>60n to get 19>089
Explanation:
show your full steps
Answer:
x = 13552.6 m
Explanation:
This is a projectile throwing exercise
Let's start by looking for the time it takes for the pump to reach the ground y = 0
y = y₀ + v_{oy} t - ½ g t²
as the plane flies horizontally the vertical speed is zero
0 = y₀ + 0 - ½ g t²
t = [tex]\sqrt{2y_o/g}[/tex]
t = [tex]\sqrt{2 \ 10000/9.8}[/tex]
t = 45.175 s
with this time we can find the distance it travels horizontally
x = v₀ₓ t
x = 300 45,175
x = 13552.6 m
the bomb must be dropped at this distance before hitting the target
Lực tương tác giữa hai điện tích điểm khi đặt trong không khí là 1,5 N. Nhúng hai điện tích đó vào môi trường điện môi có hằng số điện môi là 3 thì lực tương tác giữa chúng là bao nhiêu?
Answer:
The force is now 0.5 N.
Explanation:
Force = 1.5 N
dielectric constant , k = 3
Let the two charges are q and q' and the distance between them is r.
The electrostatic force between the two charges is given by
[tex]F \alpha \frac{ q q'}{r^2}..... (1)[/tex]
When a dielectric material is inserted between the two charges, the new force is
[tex]F' \alpha \frac{ q q'}{kr^2}..... (2)[/tex]
From (1) and (2)
F' = F/K = 1.5/3 = 0.5 N
Leakage of liquid petroleum gas can be detected from a distance . name the process
Answer:
ultrasonic
Explanation:
they detect the acoustic emission created when a pressured gas expands in a low pressure area through a small orifice(the leak).
The figure shows a graph of the angular velocity of a rotating wheel as a function of time. Although not shown in the graph, the angular velocity continues to increase at the same rate until t = 8.6 s. What is the angular displacement of the wheel from 0 to 8.6 s?
Answer:
θ = 33.54 rad
Explanation:
This is a circular motion exercise
θ= θ₀ + w₀ t + ½ α t²
suppose that for t = 0 the body is at its initial point θ₀ = 0 and from the graph we see that the initial angular velocity w₀ = -9.0 rad / s
we look for the angular acceleration,
α = [tex]\frac{\Delta w}{ \Delta t}[/tex]
from the graph taken two points
α = [tex]\frac{0 - (-9.0)}{3.0 - 0}[/tex]
α = 3 rad / s²
we substitute in the first equation
θ = 0 -9 t + ½ 3 t²
the displacement is requested for t = 8.6 s
θ = = -9 8.6 + 3/2 8.6²
θ = 33.54 rad
The angular displacement of the wheel from 0 to 8.6s is 33 radians.
Given to us
t = 8.6s
Acceleration of the wheelWe know acceleration is the ratio of velocity and time, therefore, the slope of the velocity-time graph will give us acceleration, therefore,
At point t=3, ω = 0
At point t = 5, ω = 6
Acceleration = slope of the Velocity-time graph = 3 rad/sec²
Angular displacementUsing the equation,
[tex]\theta = \omega_0t+\dfrac{1}{2}\alpha t^2[/tex]
SUbstitute values,
[tex]\theta = (-9.0\times 8.6)+\dfrac{1}{2}(3\times 8.6^2)\\\theta = 33\rm\ radians[/tex]
Hence, the angular displacement of the wheel from 0 to 8.6s is 33 radians.
Learn more about Angular displacement:
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f(x)=
[tex]f{x} = \sqrt{x} [/tex]
help me with this please
Answer:
Where is the Question?
Explanation:
I am glad to h help you out.
Answer:
Sorry is there any attachments to put with this question, If please publish question properly please so that brainly answerers will know what to answer.
you are traveling in a convertible with the top down. the car is moving at a constant velocty of 25 m/s due east along falt ground. you throw a tennis ball straight upward at a speed of 15 m/swhen the ball just leaves your hand, what is the speed of the ball as measured by an observer on the side of the road
Answer:
Teh velocity of ball with respect to the ground is 29.2 m/s.
Explanation:
Velocity of car, vc = 25 due m/s east
velocity of ball with respect to car, v(b,c) = 15 m/s due Z axis
Write the velocities in the vector form
[tex]\overrightarrow{v}_{c}=25 \widehat{i}\\\\\overrightarrow{v}_{(b,c)}=15 \widehat{k}[/tex]
The velocity of ball with respect to ground is
[tex]\overrightarrow{v}_{(b,c)}= \overrightarrow{v}_{(b,g)}-\overrightarrow{v}_{(c,g)}\\\\15 \widehat{k} = \overrightarrow{v}_{(b,g)} - 25 \widehat{i}\\\\\overrightarrow{v}_{(b,g)} = 25 \widehat{i} + 15 \widehat{k}\\\\v_{(b,g)}=\sqrt{25^2 + 15^2}=29.2 m/s[/tex]