Answer:
L = 4.58 x 10⁴ kg.m²/s
Explanation:
The angular momentum is given by the formula:
L = mvr
but, v = rω
Therefore,
L = mr²ω
where,
L = Angular Momentum of the person = ?
m = mass of person = 99 kg
r = radius of earth = 6.37 x 10⁶ m
ω = Angular Speed of Earth's Rotation = θ/t
Since, earth completes 1 rotation in 1 day. Hence,
ω = (2π rad/1 day)(1 day/24 h)(1 h/3600 s)
ω = 7.27 x 10⁻⁵ rad/s
Therefore,
L = (99 kg)(6.37 x 10⁶ m)²(7.27 x 10⁻⁵ rad/s)
L = 4.58 x 10⁴ kg.m²/s
11. A 100-W incandescent light bulb has a cylindrical tungsten filament 30.0 cm long, 0.40 mm in diameter, and with an emissivity of 0.26. (a) What is the temperature of the filament
Answer:
T = 556K
Explanation:
For this exercise let's use Stefan's law
P = σ A e T⁴
where the stafan-Boltzmann constant is 5,670 10⁻⁸ W / m² K⁴.
In this case the area of a circular cylinder is
A = π r²
the radius is
r = d / 2 = 0.150 m
A = π (0,150)²
A = 7.0685 10⁻² m²
let's clear
T⁴ = P /σ A e
T⁴ = 100 / (5.670 10⁻⁸ 7.0685 10⁻² 0.26)
T⁴ = 9.5966 10¹⁰ = 959.66 10⁸
T = 5.56 102 K
T = 556K
The temperature of the filament is 366.3 K
Using the equation for radiated power, P
P = σεAT⁴ where σ = Stefan-Boltzmann constant = 5.67 × 10⁻⁸ W/m²K⁴, ε = emissivity = 0.26, A = area of cylindrical tungsten filament = πDh (since it radiates through its sides)where D = diameter of tungsten filament = 0.40 mm = 0.4 × 10⁻³ m and h = length of tungsten filament = 30.0 cm = 0.3 m and T = temperature of tungsten filament.
Since we require the temperature of the filament, making T subject of the formula, we have
T = ⁴√(P/σεA)
T = ⁴√(P/σεπDh)
Since P = 100 W, substituting the values of the variables into the equation, we have
T = ⁴√(P/σεπDh)
T = ⁴√(100 W/5.67 × 10⁻⁸ W/m²K⁴× 0.26 × π× 0.4 × 10⁻³ m × 0.3 m)
T = ⁴√(100 W/0.5558 W/K⁴ × 10⁻⁸)
T = ⁴√179.93 × 10⁸ K⁴)
T = 3.663 × 10² K
T = 366.3 K
So, the temperature of the filament is 366.3 K
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Consider a 75.5-kg man standing on a spring scale in an elevator. Starting from rest, the elevator ascends, attaining its maximum speed of 1.65 m/s in 0.675 s. What does the spring scale register in pounds during these 0.675 s?
Answer:
208.08 pounds
Explanation:
Given that,
Mass of a man, m = 75.5 kg
Starting from rest, the elevator ascends, attaining its maximum speed of 1.65 m/s in 0.675 s.
We need to find the value of spring scale during these 0.675 s.
As the elevator ascends, net force will be given by :
F = mg + ma
a can be calculated as follows :
[tex]a=\dfrac{1.65-0}{0.675}\\\\a=2.45\ m/s^2[/tex]
So,
F = 75.5[(9.81) + (2.45)]
F = 925.63 N
We know that,
1 N = 0.224 Pounds
It means, 925.63 N = 208.08 pounds
So, the spring scale will register 208.08 pounds.
Which of the following is not permitted, based on the second law of
thermodynamics?
A. Heat flowing from cold to hot
B. A machine that is 80% efficient
C. Heat being completely converted into mechanical energy
D. Heat flowing from hot to cold
Answer:
A. Heat flowing from cold to hot
Explanation:
The second law of thermodynamics speaks about entropy and directions of processes. These directions go only in one direction, just as time moves only in one direction, as we know it. It is impossible to see time moving forward in a different sense. In the same way, the processes associated with heat transfer, go in a single direction this direction is associated with bodies at different temperatures. Where heat is transferred from a higher temperature body to a lower temperature body.
Heat transfer processes from a cold body to a hot body, do not exist and can not be achieved in a natural way.
Answer:
C
Explanation:
A plane flies from NY to LA at a constant speed of 800 km/hr. How long will it take a plane to fly 4200 km?
Answer: i don’t know the answer but
Explanation:
Divide the distance by the speed. That gives the travel time.
t = d/v = (4200 km) / (800 km/hr) = ? hrs
Which particles determine the atomic number of an element?
(2 Points)
Protons only
Neutrons and protons
Neutrons only
Protons and electrons
Answer:
protons and electrons
Assume that the left side of your heart creates a pressure of 118 mm Hg by exerting a force directly on the blood over an effective area of 16.0 cm^2. What force does it exert to accomplish?
Answer:
251.5 x 10⁻⁴ N
Explanation:
Pressure = Force / surface area
Force = pressure x area
pressure = 118 mm of Hg
= .118 x 13.6 x 9.8 N / m²
= 15.72 N / m ²
area = 16 x 10⁻⁴ m²
Force = 15.72 x 16 x 10⁻⁴
= 251.5 x 10⁻⁴ N .
A wagon having a mass of 32 kg is accelerated across a level road at 0.50 m/s2 . What net force acts on the wagon horizontally?
Answer:
16 NExplanation:
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 = 32 × 0.5
We have the final answer as
16 NHope this helps you
a car accelerates from a standstill to 60 km/hr in 10 seconds. what is the cars acceleration
What is the average velocity in the time interval 3 to 4
seconds?
Answer:
0 m/s.
Explanation:
The average velocity from 3 to 4 seconds is 0 m/s.
A refrigerator draws 4.5 A of current while operating on a 120-V power line. If the refrigerator runs 50% of the time and electric power costs $0.15/kWh, how much does it cost to run this refrigerator for a 30-day month
Answer:
$ 29.16
Explanation:
The following data were obtained from the question:
Current (I) = 4.5 A
Voltage (V) = 120 V
Time (t) = 30 days
1 KWh = $ 0.15
Cost for 30 days =.?
From the question given above, we were told that the refrigerator runs 50% of the time.
Thus, the time of operation of the refrigerator will be:
Time (t) = 30 × 50% = 30 × 50/100
= 15 days.
Next, we shall convert 15 days to hours. This can be obtained as follow:
1 day = 24 h
15 days = 15 days × 24 h / 1 day
15 days = 360 h
Next, we shall determine the energy consumed in KWh This can be obtained as follow:
Current (I) = 4.5 A
Voltage (V) = 120 V
Time (t) = 360 h
Energy (E) =?
E = ivt
E = 4.5 × 120 × 360
E = 194400 Wh
Next, we shall convert 194400 Wh to KWh. This can be obtained as follow:
1000 Wh = 1 KWh
Therefore,
194400 Wh = 194400 Wh × 1 KWh/ 1000 Wh
194400 Wh = 194.4 KWh
Thus the energy consumed is 194.4 KWh
Finally, we shall determine the cost of energy consumed. This can be obtained as follow:
From the question given above,
1 KWh cost $ 0.15
Therefore, 194.4 KWh will cost = 194.4 KWh × $ 0.15 = $ 29.16
Therefore, the cost of running the refrigerator for 30 days is $ 29.16
A quarter is tossed up from the roof of a skyscraper and hits the sidewalk below. Which of the following graphs best shows the velocity v vv of the quarter from when it is tossed up until it reaches the ground?
Answer:
pic
Explanation:
The graph which best shows the velocity v of the quarter from when it is tossed up until it reaches the ground is attached in the answer.
What is velocity?
Velocity is the time rate of change of displacement. The displacement and velocity both are vector quantities. They represent magnitude and direction as well.
A quarter is tossed up from the roof of a skyscraper and hits the sidewalk below.
The velocity will decrease with the time linearly.
The graph which best shows the velocity v of the quarter from when it is tossed up until it reaches the ground is attached in the solution.
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One particle, of mass m , moves with a speed v in the x-direction, and another particle, of mass 2 m , moves with a speed v/2 in the y-direction. what is the velocity of the center of mass of these two particles?
Given :
One particle, of mass m , moves with a speed v in the x-direction, and another particle, of mass 2 m , moves with a speed v/2 in the y-direction.
To Find :
The velocity of the center of mass of these two particles.
Solution :
Speed of mass m, [tex]v\ \hat i[/tex].
Speed of mass 2m , [tex]\dfrac{v}{2}\ \hat{j}[/tex] .
Speed of center of mass is given by :
[tex]v_{cm }= \dfrac{m\times( v\ \hat{i}) + 2m \times \dfrac{v}{2}\ \hat{j} }{m + 2m}\\\\v_{cm}=\dfrac{v( \hat{i} + \hat{j})}{3}[/tex]
Hence, this is the required solution.
The velocity of the center of mass of these two particles will be [tex]\rm v_{cm}= \frac{v(\vec i+\vec j)}{3}[/tex]
What is velocity?The change of displacement with regards to time is defined as speed. Speed is a scalar quantity. It is a time-based component. Its unit is m/sec.
The given data in the problem is
[tex]\rm V_i[/tex] is the speed of mass m
[tex]\rm \frac{v}{2} \hat j[/tex] is the speed of mass 2m
Speed of the center of mass will be;
[tex]\rm v_{cm}=\frac{m \times (v \hat i)+2m \times \frac{v}{2}\hat j }{m+2m} \\\\ \rm v_{cm}= \frac{v(\vec i+\vec j)}{3}[/tex]
Hence the velocity of the center of mass of these two particles will be [tex]\rm v_{cm}= \frac{v(\vec i+\vec j)}{3}[/tex].
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An atomic nucleus suddenly bursts apart (fission) into two pieces. Piece A with mass mA travels to the left with a speed of vA. Piece B with mass mB travels to the right with speed vB. Show the velocity of piece B in terms of mA, mB and VA.
Solution:
Consider that the nucleus is not acted by an external force. Thus, momentum is conserved, so: pBf + pAf = 0
Substituting the expression for momentum results to
mBv (_______) + (_________) mAv (______) = 0
Deriving the expression for the velocity of piece B results to
v(_____) =(mA/m ______)vA
Answer:
[tex]v_{B} = \frac{m_{A}v_{A}}{m_{B}}[/tex]
Explanation:
We can apply the law of conservation of momentum on the nucleus in its initial and final state of nucleus:
Initial Momentum = Final Momentum
momentum of nucleus before bursting = momentum of piece A + momentum of Piece B
[tex](m_{nucleus})(velocity of nucleus) = m_{A}v_{A} + m_{B}v_{B}\\[/tex]
since, nucleus was initially at rest. Therefore,
velocity of nucleus = 0 m/s
and due to opposite direction of forces:
Vb = - Vb
Therefore,
[tex](m_{nucleus})(0) = m_{A}v_{A} - m_{B}v_{B}\\\\m_{A}v_{A} = m_{B}v_{B}\\\\v_{B} = \frac{m_{A}v_{A}}{m_{B}}[/tex]
A 100-turn coil has a radius of 7.50 cm and a resistance of 50.0 W. At what rate must a perpendicular magnetic field change to produce a current of 5.00 A in the coil
Answer:
dB / dt = -141.47 T / s
Explanation:
For this exercise let's use Faraday's law to calculate the induced electromotive force
E = - N dФ / dt
the magnetic flux is
Ф = B. A
in this case the direction of the field and the normal to area are parallel so the scalar product is reduced to the algebraic product
Ф = B A
we substitute
E = - N A dB / dt
the area of the loop is
A = π r²
we substitute
E = - N π r² dB / dt
in the exercise indicate that the resistance of the coil is R = 50.0 Ω,
E = i R
we substitute
i R = -N π r² dB / dt
dB / dT = - i R / N π r²
let's calculate
dB / dt = - 5.00 50.0 / (100 π 0.075²)
dB / dt = -141.47 T / s
Astronomers discover a bright X-ray source in the Milky Way. They see no counterpart in the optical bands, but it has another star orbiting it, and they determine that the X-ray source has a mass of 10 MSun. What is the most likely origin of the X-rays?
a. a black hole
b. a neutron star
c. a white dwarf
d. a gamma-ray burst
Answer:
a. a black hole
Explanation:
X-ray emission from the central degrees of the Milky Way Bright X-ray emission traces the coherent edge brightened shell-like feature, dubbed the northern chimney, located north of Sgr A* and characterized by a diameter of about 160 pc. On the opposite side, the southern chimney appears as a bright linear feature. Bright X-ray emission is observed at high latitude
How fast would a rock fall in a vacuum? Based on this, why would Aristotle say that there could be no such thing as a vacuum?
Answer:
In real measurements, the acceleration that is measured is always less than the acceleration of gravity, therefore there must be a force that opposes the movement, which is why Aristotle says that vacuum stenos
Explanation:
When a rock starts the vacuum, there are no friction forces that make its movement, therefore, if close to the Earth, the rock has an acceleration equal to the acceleration of gravity.
In real measurements, the acceleration that is measured is always less than the acceleration of gravity, therefore there must be a force that opposes the movement, which is why Aristotle says that vacuum stenos
A 337 nm nitrogen laser puts out 5.00 W of power with a beam 5.90 mm in diameter. The beam is pointed directly at a pinhole which has a diameter of 1.10 mm. How many photons of light will travel through the pinhole per second? Assume that the intensity of the light is equally distributed across the whole area of the beam.
Answer:
#_foton2 = 2.96 10¹⁶ photon / s
Explanation:
We are going to solve this exercise in parts, first we will calculate how many photons are in the beam and then the amount that pass through the pinhole.
To find the energy of a photon, let's use the Planck relationship
E = h f
c = λ f
we substitute
E₀ = h c /λ
E₀ = 6.63 10⁻³⁴ 3 10⁸/337 10⁻⁹
E₀ = 5.90 10⁻¹⁹ J
Now we can use a direct ratio rule to find out the number of photons in the beam. If 1 photon has an energy E₀, how many photons are in an energy 5.00W
# _foton = 1 5/ E₀ = 1 5 / 5.90 10⁻¹⁹
#_foton = 8.5 10¹⁸ photons / s
This number of photons is uniformly distributed in the area of the circle with diameter 5.90mm = 5.90 10⁻³m
R= d/2= 2.95 10⁻³ m
r = d/2 = 0.55 10⁻³ m
let's find the beam area
A = π R²
A = π (2.95 10⁻³)²
A = 2.73 10⁻⁵ m²
the pinhole area
a = π r²
a = π (0.55 10⁻³)²
a = 9.50 10⁻⁷ m²
Let's use another direct ratio (rule of three) if there are 8.5 1018 photons / s in an area A how many photons pass through the area at
# _foton2 = 8.5 10¹⁸ a / A
# _fotn2 = 8.5 10¹⁸ 9.50 10⁻⁷ /2.73 10⁻⁵
#_foton2 = 2.96 10¹⁶ photon / s
What season is it in your town when it is fall in the Southern Hemisphere
Answer:
i am in the southern hemisphere
Explanation:
Answer:
its winter ................
Arocket with an initial velocity of 20 m/s another engine that gives it an acceleration of 4 m/s ^ 2 over 10 secondsHow far did the rocket travel during this time
Answer:
50m
Explanation:
Given parameters:
Initial velocity = 20m/s
Acceleration = 4m/s²
Time = 10s
Unknown:
Distance traveled by the rocket = ?
Solution:
To solve this problem use the expression below;
v² = u² + 2as
v is the final velocity
u is the initial velocity
a is the acceleration
s is the distance
final velocity = 0
Insert the parameters and solve;
0² = 20² + 2 x 4 x s
-400 = 8s
s = 50m
Disregard the negative sign because distance cannot be negative.
A 200.0 kg sled is being towed horizontally with a force of 25 N for 120 m in 30 seconds. What is the power of the applied force?
Answer:
.
Explanation:
What are the results if you fail to turn the Bucky on?
Answer:
♡ here's your answer ♡
if you fail to turn the bucky on, it might result in your life being dangered since if in one case, your protecting yourself and you don't have it on, you could get killed ☆
- madeline/madi
✧･ﾟ: *✧･ﾟ:･ﾟ✧*:･ﾟ✧･ﾟ
Explanation:
cloudy nights are usually warm because
Answer:
When you have a cloudy night, the clouds prevent heat from escaping through the atmosphere and into space.
The clouds act like a blanket and trap the heat it, and that is why every time you have a cloudy night, it is always warmer than a clear night.
Based on the information in the passage, What is true of gases
Answer:
that gases are gases
Explanation:
Answer:
A. Some, but not all gases are harmful to humans.
Explanation:
4. Name three things that all games, no matter where they are played around the world, have in common.
Answer:
Key components of games are goals, rules, challenge, and interaction.
Explanation:
Hope I helped.
Answer:
the name of the games are goals, rules, challenges and interaction and mabe there can be more.
Explanation:
I hope this helped your day better this is the correct answer i got it correct on the test.
A student is planning to make changes to a circuit. Which change will
increase the resistance?
A. Replace the wire with one that is longer.
B. Swap ne positions of the battery and the switch.
C. Replace the wire with one that is shorter.
D. Swap the positions of the lightbulb and the switch.
Answer:
A)
Explanation:
This is because the longer the wire is, the more resistance there is for the electricity to run through.
The student can increase the resistance by replacing the wire with one that is longer. Thus, option A is correct.
What is Ohm's law?The voltage across a conductor, according to Ohm's law, is precisely proportional to the current that passes through it.
A wire's resistance is inversely correlated with its cross-sectional area and directly correlated with its length. Most conductors have a resistance to the flow of an electric current through them. As the wire's length increases, the resistance in the wire rises.
However, according to Ohms law V=IR, a wire's length increases its resistance while decreasing its current for a given potential difference (voltage).
Therefore, replacing the wire with a longer one will increase resistance if a student plans to modify a circuit.
Thus, option A is correct.
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in the velocity and acceleration are in the same direction the speed of the object decreases
true or false
Answer:
False
Explanation:
Im pretty sure the answer is false
please answer this question
Answer:
Pic not clear.........
A 5000 kg meteorite falls toward the earth. What is the magnitude of the earth's acceleration just before impact? The earth's mass is 5.98 × 10^24 kg.
Answer:
8.193x10^-21m/s²
Explanation:
We have it that the gravitational force that is acting on this object is equal to the earth's gravitational force.
We start by using this formula
Ma = mg
We make a the subject of formula
a = mg/M
m = 5000kg
g = 9.8
M = 5.98x10^24kg
mg = 5000x9.8
= 49000
49000/5.98x10^24
= 8.193x10^-21m/s²
The magnitude of the earth's acceleration is 8.20 × 10^27
The parameters given in the question are;
mass= 5000 kg
g= 9.81
earth's mass= 5.98 × 10∧ 24
The formula is
= mass × acceleration due to gravity/earth's mass
= 5000 × 9.81/ 5.98^24
= 49,050/5.98 × 10^24
= 8.20 × 10^27
Hence the magnitude of the earth's acceleration just before impact is 8.20 × 10^27
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The relative age of lower layers of rock is _______ than the
relative age of rocks above them.
Answer:
the relative age of lower layers of rock is more than the relative age of rocks above them.
As you get older your muscles grow.
True
True
False
Answer:
f
Explanation:
Answer:
yeah but if you get in your 30s you start to lose muscles