For a lawnmower that produces noise at a level of 91.0 dB, the intensity of this sound is mathematically given as
I=1.26*10^-3W/m^2
What is the intensity of this sound in watts per meter squared?Generally, the equation for the sound is mathematically given as
B=(10dB)log10(1/1_0)
Therefore
91/10=log(I/10^{-12})
I=1.26*10^-3W/m^2
In conclusion, the intensity
I=1.26*10^-3W/m^2
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QUESTION 9
What determines the evolutionary path a star takes through its life?
O a. Diameter
O b. Who made it
O c. Color
O d. Mass
Answer:
Mass
Explanation:
In the core of the red giant, helium fuses into carbon. All stars evolve the same way up to the red giant phase. The amount of mass a star has determines which of the following life cycle paths it will take from there. The life cycle of a low mass star (left oval) and a high mass star (right oval).May 7, 2015
When you jump, you exert a pushing force against the ground. Gravity pulls you back down. Why can a person jump higher on the moon than on Earth?
Answer:
This is because the force of gravity is much less on the moon than on the earth, therefore the person wont be pulled down much and will jump higher
Answer: This is because the force of gravity is much less on the moon than on the earth, therefore the person won't be pulled down much and will jump higher.
17. How long will it take for an object accelerating at a constant rate of 5 m/s to change its velocity from 0 to 6 m/s? (A) 0.6s (B) 1.2 s (C) 2.4 s (D) 3.6 s (E) 4.8 s
Answer:
(B)
Explanation:
Time = change of velocity ÷ acceleration
= (6-0) ÷ 5
= 1.2
1.2 s it take for an object accelerating at a constant rate of 5 m/s to change its velocity from 0 to 6 m/s.
Hence, the correct option is D.
To calculate the time it takes for an object to change its velocity from 0 to 6 m/s, we can use the formula:
time = change in velocity / acceleration
Given that the change in velocity (Δv) is 6 m/s and the acceleration (a) is 5 m/s², we can plug these values into the formula:
time = 6 m/s / 5 m/s²
time = 1.2 seconds
Therefore, 1.2 s it take for an object accelerating at a constant rate of 5 m/s to change its velocity from 0 to 6 m/s.
Hence, the correct option is D.
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above
3. DIRECTIONS: Read the following two statements carefully and choose the correct options.
Statement 1: In a room containing air, heat can go from one place to another by radiation only.
Statement 2: In convection, heat is transferred from one place to other by actual motion of the
molecules in the heated material.
A) Statement (1) is correct while statement (2) is incorrect.
B) Statement (2) is correct while statement (1) is incorrect.
C) Both statements are correct
D) Both statements are incorrect.
When is an object positively charged?
Answer:
when it has a fewer amount of electrons than protons
1) How many joules of heat are required to raise the temperature of 550 g of water from
12.7 °C to 28.8°C ? Specific heat of liquid water is 4.184 J/g °C.
Answer:
Explanation:
You can use [tex]Q = mc\Delta T=(550)(4.184)(28.8-12.7)=37049.32[/tex] joule.
What is created when an object travels faster than the speed of sound
Answer:
Explanation:
Answer: Sonic Boom.
When the object reaches the speed of sound, air cannot readily move out of the way and a shock wave is formed. When the object is moving faster than sound, the resulting sounds travel behind the object, creating a sonic boom.
Which best illustrates projectile motion?
A pictorial diagram showing a hot air balloon in four different positions, each the same height from the ground and equally spaced.
A pictorial diagram with a rocket launched straight upward. The first three positions of the rocket are shown with equal spacing between them.
A pictorial diagram with a person swimming and position shown in equal time intervals and equally spaced.
A pictorial diagram of a person hopping sideways at 5 different positions. The start and end positions are on the ground. The third image is the highest off the ground.
The pictorial diagram with a rocket launched straight upward, showing the first three positions of the rocket with equal spacing between them, best illustrates projectile motion. In this case, the rocket is projected upward into the air, and its path follows a parabolic trajectory due to the influence of gravity.
What is projectile motion?Projectile motion refers to the motion of an object that is thrown, launched or otherwise projected into the air and then moves under the influence of gravity alone. In this type of motion, the object moves along a curved path, called a parabola, due to the combined effect of its initial velocity and the force of gravity acting on it.
When a rocket is launched straight upward, it experiences a projectile motion. The rocket's initial velocity is upwards, but gravity causes it to decelerate until it eventually stops at the highest point of its trajectory. The rocket then starts to fall back down, accelerating due to gravity until it reaches the ground. If we take three equal intervals of time, we can show the rocket's positions at those times. Initially, the rocket will be moving upwards with a decreasing velocity, then it will reach its maximum height before falling back down with an increasing velocity.
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Answer: I believe it should be the final answer,
A pictorial diagram of a person hopping sideways at 5 different positions. The start and end positions are on the ground. The third image is the highest off the ground
Explanation:
Many U.S. college freshman say that "being well-off" financially is an essential life goal and that "making more money" was a very important factor in their decision to attend college. According to Abram Maslow, which meta-needs are being fulfilled by "making more money"?
Based on research by Abraham Maslow, the meta-needs which are fulfilled by "making more money" are none of the meta-needs.
What are meta-needs?According to Abraham Maslow, meta-needs are human needs that relate to beauty, knowledge and creativity.
All of these can be met without having to make more money so it stands to reason that there are no meta-needs that can be met by making more money.
The main need that is met by making more money according to Maslow is Security and it is not a meta-need.
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According to Sigmund Freud, memories that easily surface into everyday thought are which part of the mind?
The conscious mind contains all of the thoughts, memories, feelings, and wishes of which we are aware at any given moment. This is the aspect of our mental processing that we can think and talk about rationally. This also includes our memory, which is not always part of consciousness but can be retrieved easily and brought into awareness.
hope it helps...!!!
According to Sigmund Freud, memories that easily surface into everyday thought are a conscious part of the mind.
What is conscious mind?
At any given time, the conscious mind contains all of our thoughts, memories, feelings, and wants.
This is the element of our brain functioning that we can reasonably think about and discuss. This includes our memories, which are not always conscious but can be readily recovered and brought into awareness.
Memories that easily emerge into everyday consciousness, according to Sigmund Freud, are a conscious element of the mind.
Hence, memories that easily surface into everyday thought are a conscious part of the mind.
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3. Hahn determined that barium (atomic number 56) was one of the elements created when a uranium atom (atomic number 92) split . Use a periodic table to determine the other element that was created during this process.
According to a periodic table, Krypton was created during the fission of Uranium.
What is the atomic number?
Atomic number is a characteristic associated with an element and indicates its number of protons, when a fision occurs, the total number protons is conserved.
Thus, the fission of uranium is led by two elements with atomic numbers 56 and 36. According to a periodic table, those atomic numbers are associated to elements Barium (Ba) and Krypton (Kr), respectively.
According to a periodic table, Krypton was created during the fission of Uranium. [tex]\blacksquare[/tex]
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3. Use the information about acceleration shown in Figure 2 as evidence to determine the magnitude of the net force acting on the scooter.
a. The net force from t = 1 to t = 6 s is 112 N
b. The net force from t = 7 to t = 12 s is 0 N
ForceForce is that thing which causes a change in motion of an object. The net force is given mathematically as F = ma where
m = mass of object and a = acceleration of objectNet forceThis is the resultant sum of all the forces acting on an object. It is also given by F = ma where
m = mass of object and a = net acceleration of objecta. Net force from t = 1 to t = 6 sThe net force from t = 1 to t = 6 s is 112 N
From the table from time t = 1 to t = 6 s, the acceleration a = 1.4 m/s². Since m = 80 kg,
F = ma
= 80 kg × 1.4 m/s²
= 112 kgm/s²
= 112 N
So, the net force from t = 1 to t = 6 s is 112 N
b. Net force from t = 7 to 12 sThe net force from t = 7 to t = 12 s is 0 N
From the table from t = 7 to t = 12 s, the acceleration a = 0 m/s²
Since m = 80 kg,
F = ma
= 80 kg × 0 m/s²
= 0 kgm/s²
= 0 N
So, the net force from t = 7 to t = 12 s is 0 N
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you move a 25 N object 5.0 meters. how much work did you do?
Answer:
125J
Explanation:
[tex]work \: = force \: \times distance \\ = 25 \times 5 \\ = 125joules[/tex]
Can a machine multiply both force and speed at same time??
Answer:
No
Explanation:
It is not possible for a machine to act as a force multiplier and speed multiplier simultaneously. This is because machines which are force multipliers cannot gain in speed and vice-versa.
It is not possible for a machine to act as a force multiplier and speed multiplier simultaneously. This is because machines which are force multipliers cannot gain in speed and vice-versa.
1. A listener stands 20.0 m from a speaker that pumps out music with a power output of 100.0 W.
a. What is surface area being vibrated by the time the sound reaches the listener (you may
have to look up the equation for the area of a sphere).
b. What is the intensity of the sound wave as it reaches the person listening?
c. What is the relative intensity of the sound as heard by the listener?
2. A police car siren has a frequency of 512 Hz. They are chasing a suspect at 65.0 m/s.
a. What is the speed of sound if the air temperature is 15.0o?
b. If the suspect is running away from the police car at 10.0 m/s, what is the frequency of
the sound he hears?
(1.a) The surface area being vibrated by the time the sound reaches the listener is 5,026.55 m².
(1.b) The intensity of the sound wave as it reaches the person listening is 0.02 W/m².
(1.c) The relative intensity of the sound as heard by the listener is 103 dB.
(2.a) The speed of sound if the air temperature is 15⁰C is 340.3 m/s.
(2.b) The frequency of the sound heard by the suspect is 614.3 Hz.
Surface area being vibratedThe surface area being vibrated by the time the sound reaches the listener is calculated as follows;
A = 4πr²
A = 4π x (20)²
A = 5,026.55 m²
Intensity of the soundThe intensity of the sound is calculated as follows;
I = P/A
I = (100) / (5,026.55)
I = 0.02 W/m²
Relative intensity of the sound[tex]B = 10log(\frac{I}{I_0} )\\\\B = 10 \times log(\frac{0.02}{10^{-12}} )\\\\B = 103 \ dB[/tex]
Speed of sound at the given temperature[tex]v= 331.3\sqrt{1 + \frac{T}{273} } \\\\v = 331.3\sqrt{1 + \frac{15}{273} } \\\\v = 340.3 \ m/s[/tex]
Frequency of the soundThe frequency of the sound heard is determined by applying Doppler effect.
[tex]f_o = f_s(\frac{v \pm v_0}{v \pm v_s} )[/tex]
where;
-v₀ is velocity of the observer moving away from the source-vs is the velocity of the source moving towards the observerfs is the source frequencyfo is the observed frequencyv is speed of sound[tex]f_0 = f_s(\frac{v-v_0}{v- v_s} )[/tex]
[tex]f_0 = 512(\frac{340.3 - 10}{340.3 - 65} )\\\\f_0 = 614.3 \ Hz[/tex]
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In a steam engine, steam in a cylinder expands against a piston, exerting 10 atm of external pressure. The volume of the cylinder increases by 10 L and simultaneously the steam cools, losing 3,000 kJ of energy to the surroundings. What is the change in energy of the steam
If steam in a cylinder expands against a piston, exerting 10 atm of external pressure, the change in energy of the steam is mathematically given as
dE= -3010 kJ
What is the change in energy of the steam?Generally, the equation for the workdone is mathematically given as
Work = - (pressure * Volume)
Therefore
w= - (10 x 10)
w= -100 L atm
In conclusion
dEnergy = q + work
dE = -3000 + -10.13
dE= -3010 kJ
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A sound wave has a frequency of 350 Hz and a wavelength of 2.25m. At what speed will the
sound wave move? Show your work.
Answer:
787.5m/s
Explanation:
Speed = wavelength x frequency
speed = 2.25m x 350 Hz
= 787.5m/s
What does the atomic numbers equal? A number of protons in the atomic nucleus B number of protons and neutrons in the atomic nucleus C number of neutrons in the atomic nucleus
number of protons
explanation:the atomic number of an atom is equal to the number of protons
If you go into a store to buy a digital thermometer and there are 8 instruments of the same brand and model, at the same price, but they indicate different temperature values, explain which one you choose and why.
Answer: I would buy the thermometer with the most features because they all cost the same price so why not you getting more than what you are paying for than buying something the same but with less feature and things it can do for the same price.
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Explanation:
An eletrical conductor is a material that allows _____ to travel through it freely
Answer:
it allows electric charges to travel through freely
If a snowboarder’s initial speed is 4 m/s and comes to rest when making it to the upper level. With a slightly greater initial speed of 5 m/s, the snowboarder is moving to the right on the upper level. His final speed in this case is 3 m/s. Suppose this situation is repeated on planet Epsilon, where gravity is less than gravity on earth.
A. Would the height of the hill on Epsilon cause a reduction in speed from 4 m/s to 0 greater than, less than, or equal to the height of the corresponding hill on earth? Explain.
B. Consider the hill on Epsilon discussed in part A. If the initial speed at the bottom of the hill is 5 m/s, will the final speed at the top of the hill be greater than, less than, or equal to 3 m/s? Explain.
(a) At a corresponding hill on Earth and a lesser gravity on planet Epslion, the height of the hill will cause a reduction in the initial speed of the snowboarder from 4 m/s to a value greater than zero (0).
(b) If the initial speed at the bottom of the hill is 5 m/s, the final speed at the top of the hill be greater than 3 m/s.
Conservation of mechanical energy
The effect of height and gravity on speed on the given planet Epislon is determined by applying the principle of conservation of mechanical energy as shown below;
ΔK.E = ΔP.E
¹/₂m(v²- u²) = mg(hi - hf)
¹/₂(v²- u²) = g(0 - hf)
v² - u² = -2ghf
v² = u² - 2ghf
where;
v is the final velocity at upper levelu is the initial velocityhf is final heightg is acceleration due to gravitywhen u² = 2gh, then v² = 0,
when gravity reduces, u² > 2gh, and v² > 0
Thus, at a corresponding hill on Earth and a lesser gravity on planet Epslion, the height of the hill will cause a reduction in the initial speed of the snowboarder from 4 m/s to a value greater than zero (0).
Final speedv² = u² - 2ghf
where;
u is the initial speed = 5 m/sg is acceleration due to gravity and its less than 9.8 m/s²v is final speedhf is equal heightSince g on Epislon is less than 9.8 m/s² of Earth;
5² - 2ghf > 3 m/s
Thus, if the initial speed at the bottom of the hill is 5 m/s, the final speed at the top of the hill be greater than 3 m/s.
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A wheel rotates at 24 revolutions every 3 minutes. This is equivalent to
Physics Help anyone?
Hi there!
A)
At this point, the pilot is experiencing a DOWNWARD NET centripetal force (ALWAYS points towards the center of the circle) as well as a downward force due to gravity. Additionally, we can say that the normal force exerted by the seat on the pilot is its apparent weight.
[tex]\Sigma F = F_g + F_N[/tex]
**The net force is the centripetal force.
We can assign both to be positive since they work in the same direction. (Assigning down as positive in THIS situation will make things easier).
We know that:
[tex]F_c = \frac{mv^2}{r}[/tex]
Fc = Centripetal force (N)
m = mass (kg)
v = velocity (m/s)
r = radius (m)
[tex]F_g = mg[/tex]
Fg = Force due to gravity (N)
m = mass (kg)
g = acceleration due to gravity (9.81 m/s²)
Solve for mass. (Given weight)
[tex]m = \frac{F_g}{g}\\\\m = \frac{719}{9.8} = 73.367 kg[/tex]
Now, we have everything we need to solve.
[tex]\frac{mv^2}{r} = F_g + F_N \\\\\frac{mv^2}{r} - F_g = F_N\\\\F_N = \frac{(73.367)(225^2)}{3110} - 719 = \boxed{475.278 N}[/tex]
B)
Weightlessness is achieved when the pilot is in free fall. In this instance, FN (Normal force by the seat) = 0 N.
We can use the same setup as above.
[tex]\frac{mv^2}{r} = F_g + 0 (F_N)[/tex]
[tex]\frac{mv^2}{r} = mg[/tex]
Solve for 'v'.
[tex]\frac{v^2}{r} = g\\\\v = \sqrt{gr} = \sqrt{(9.81)(3110)} = \boxed{174.669 \frac{m}{s}}[/tex]
C)
At the BOTTOM, we have the force of gravity working DOWNWARD (Negative in this instance), while the centripetal force (NET FORCE) and normal force are upward (Positive). Do another summation of forces:
[tex]\Sigma F = F_N - F_g\\\\\\frac{mv^2}{r} + F_g = F_N \\\\F_N = \frac{(73.367)(225^2)}{3110} + 719 = \boxed{1913.278 N}[/tex]
The diagram shows a heating curve for water.
Which statement best describes what is happening at
segment W-X?
Heating Curve for Water
O Water is absorbing heat.
O Water is releasing heat.
O Aliquid is changing to a gas.
O A gas is changing to a liquid.
z
110
100
90
x
х
Y
80
Temperature (Cº)
70
60
50
40
w
Heat (J)
Answer:
a water is heating up
Explanation:
the water's temperature is inceasing
help me solve the following question below in the attachment
Answer:
Explanation:
The point P is influenced by two electric fields, that are from Q1 and Q2. Because Q1 is a positive point charge, the E-fields is going to the right and the E-fields from Q2 is going to the left because of negative point charge. So:
[tex]E_{1}=\frac{kQ_{1}}{R_{1}^{2}}[/tex]
[tex]E_{2}=\frac{kQ_{2}}{R_{2}^{2}}[/tex]
Where R1 = 2 + 3 = 5 m, and R2 = 3 m. With k = [tex]k=9\times 10^{9}[/tex] in [tex]Nm^{2}/C^{2}[/tex], we can obtain:
[tex]E_{1}=(9\times 10^{9})\frac{500\times10^{-6}}{25}=180\times 10^{3}[/tex] N/C (+)
[tex]E_{2}=(9\times 10^{9})\frac{100\times 10^{-6}}{9}=100\times 10^{3}[/tex] N/C (-)
So: the Electric Field at P : [tex]E_{P}=E_{1}-E_{2}=(180-100)\times 10^{3}=8\times 10^{4}[/tex] N/C in magnitude
what does a snow leopard eat?
Answer:
They eat Himalayan blue sheep, boar, deers, wild mountain goats, pikas etc.
Explanation:
a 50 kg boy runs at 3 m/s. how much momentum does he have
Answer:
150 kg-m/s
Explanation:
momentum = m * v
50 * 3 = 150
The force between a pair of charges is 900 newtons. The distance between the charges is 0.01 meters. If one of the charges is 2e-10 C what is the strength of the other charge ?
Answer:
[tex] \fbox{strength \: of \: the \: other \: charge = - 0.0196 Ke \: Coulomb}[/tex]
Explanation:
Given:
Force between pair of charges= 900 newtons
The distance between the charges = 0.01 meters
Strength of Charge first q1 = 2e-10 Coulomb
To find:
Strength of Charge second q2 = ____ Coulomb?
Solution:
We know that,
Force between two charges separate by distance r is given by the equation,
[tex]|F| = K_e \frac{q1 \cdot \: q2}{ {r}^{2} } \\ 900 =K_e \frac{(2e - 10)\cdot \: q2}{ {0.01}^{2} } \\ 900 \times {10}^{ - 4} = K_e {(2e - 10)\cdot \: q2} \\ q2 = \frac{9 \times {10}^{ - 2} }{(2e - 10) K_e} \\ \\ \fbox{We \: know \: that \: e = 2.71 } \\ substituting \: the \: value \: \\ q2 = \frac{9 \times {10}^{ - 2} }{(2 \times 2.71 - 10)K_e} \\ q2 = \frac{0.09}{ - 4.58 K_e} \\ q2 = \frac{-0.0196}{K_e}\: coulomb[/tex]
[tex] \fbox{strength \: of \: the \: other \: charge = - 0.0196 Ke \: Coulomb}[/tex]
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a 56-kg student runs at 6.2m/s, grabs a hanging 10.0m long rope, and swings out over a lake. He releases the rope when his velocity is zero.
a) what is the tension in the rope just before he releases it?
b) what is the maximum tension in the rope during the swing?
Answer:
0.52 8.9
Explanation:
calc.
The tension in the rope just before the student releases it is 576 N.
What is tension?Tension is defined in physics as the pulling force transmitted axially by a string, rope, chain, or similar object.
Just before the student releases the rope, his velocity is zero. At this point, all of his kinetic energy has been converted into potential energy. Therefore, we can write:
1/2 m [tex]v^2[/tex] = mgh
h = [tex]v^2[/tex] / (2g) = [tex](6.2 m/s)^2[/tex] / (2 x 9.8 [tex]m/s^2[/tex]) ≈ 1.95 m
m g = 56 kg x 9.8 [tex]m/s^2[/tex] ≈ 549 N
The tension required to keep the rope taut is equal to the horizontal component of the force due to the weight of the student, which is:
T = m g / cos(θ)
tan(θ) = h / L
tan(θ) = 1.95 m / 10.0 m ≈ 0.195
θ ≈ 10.9°
So, T = m g / cos(θ) ≈ 576 N
To find the maximum tension in the rope during the swing, we can use conservation of angular momentum.
L = I ω
I = (1/3) m [tex]L^2[/tex]
I = (1/3) x 10.0 kg x [tex](10.0 m)^2[/tex] ≈ 3333.3 kg[tex]m^2[/tex]
The angular velocity of the rope just after the student releases it is:
ω = v / L
ω = 6.2 m/s / 10.0 m ≈ 0.62 rad/s
L = I ω ≈ 2070 N m s
Thus, the angular momentum of the system just after the student releases the rope is 2070 N m s.
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What is the difference between magnitude of displacement and magnitude of velocity