Answer: a =0
Explanation:
An observer is standing next to the tracks, watching a train approach. The train travels at 30 m/s and blows its whistle at 8,000 Hz as it approaches and then passes by the observer without slowing down. Assuming the speed of sound is 340 m/s, how much of a frequency change did the observer hear?
7351.35Hz
f0= v-Vo/v-Vs × FSA
= 340-0 /340+30 ×8000
= 340/370× 8000
= 7351.35hz
Two stones are dropped from the edge of a 60m cliff , the second stone 1.6secon after the first . How far below the top of the cliff is the second stone when the separation between the two stone is 36m?
Answer:
The separation between the two stones is 36 m, when the second stone is approximately 10.9 m below the top of the cliff
Explanation:
The given parameters are;
The height of the cliff from which the stones are dropped, h = 60 m
The time at which the second stone is dropped = 1.6 seconds after the first
The distance below the top of the cliff when the distance between the two stones is 36 m = Required
We have;
The kinematic equation of motion that can be used is s = u·t - (1/2)·g·t²
For the first stone, we have, s₁ = u·t₁ - (1/2)·g·t₁²
For the second stone, we get; s₂ = u·t₂ - (1/2)·g·t₂²
t₁ = t₂ + 1.6
g = The acceleration due to gravity ≈ 9.81 m/s²
s = The distance below the cliff top
The initial velocity of the stones, u = 0
Let t represent the time from which the second stone is dropped at which the distance between the two stones is 36 m, we have;
s₁ = u·(t + 1.6) + (1/2)·g·(t + 1.6)²
s₂ = u·t + (1/2)·g·t²
u = 0
∴ s₁ - s₂ = 36 = (1/2)·g·(t + 1.6)² - (1/2)·g·t²
2 × 36/(g) = (t + 1.6)² - t² = t² + 3.2·t + 2.56 - t² = 3.2·t + 2.56
2 × 36/(9.81) = 3.2·t + 2.56
t = (2 × 36/(9.81) - 2.56)/3.2 = ≈ 1.49 s
t ≈ 1.49 s
s₂ = (1/2)·g·t²
∴ s₂ = (1/2) × 9.81 × 1.49² ≈ 10.9
The distance below the top of the cliff of the second stone when the the separation between the two stones is 36 m, s₂ ≈ 10.9 m.
A rod is made up of copper and wood joined together.
After the rod is heated at the join in the centre for about a minute, where would the lowest temperature be?
my views
Explanation:
Figure (8) shows a rod made up of copper and wood joined together. The rod is heated at the joint in the centre for about a minute. At which point – A, B, C or D, would it show the lowest temperature? PLEASE GIVE REASONS ALSO(MINIMUM 2)
If a lever lifts a load four times the effort applied and effort distance is 5 times the load distance, calculate its efficiency
Answer:
If effort distance was 4 times, efficiency would be 100%.
Since it takes 5 times for effort distance, efficiency drops to output/input
output is 1*F
input is (1/4*F)*5
so: F/1/5*F/4 = 4F/5F = .8 or 80%
The efficiency of the lever is 80%.
To calculate the efficiency of the lever, we can use the formula for mechanical advantage and efficiency.
Mechanical Advantage (MA) is the ratio of the load (L) to the effort (E) in a lever system:
MA = Load / Effort
Given that the load is four times the effort applied:
Load = 4 * Effort
Also, the effort distance (dEffort) is five times the load distance (dLoad):
dEffort = 5 * dLoad
Now, we can write the formula for efficiency (η) of a lever system:
Efficiency (η) = (Mechanical Advantage / Ideal Mechanical Advantage) * 100%
The Ideal Mechanical Advantage (IMA) is the ratio of the effort distance to the load distance:
IMA = dEffort / dLoad
Substitute the given values into the IMA equation:
IMA = (5 * dLoad) / dLoad
IMA = 5
Now, we can calculate the Mechanical Advantage (MA) using the relationship between the load and effort:
MA = Load / Effort
MA = (4 * Effort) / Effort
MA = 4
Finally, we can calculate the efficiency (η):
Efficiency (η) = (Mechanical Advantage / Ideal Mechanical Advantage) * 100%
η = (4 / 5) * 100%
η = 0.8 * 100%
η = 80%
The efficiency of the lever is 80%.
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how do atoms lose electrons ?
Answer:
Explanation:
By being close to an atom that will gladly take the electrons being offered.
Suppose you are talking about Be. It is in the second column. It has two outer electrons that can be given away. It will not give away one of the two remaining electrons because they are too close to the + nucleus.
Along comes a Fluorine atom. It has 7 electrons in its outer ring. The chemistry of the situation allows it to take on one of the two electrons Be is offering. It is all a matter of charges and attractions.
Another Fluorine atom will take on the remaining electron from the Be. The outer ring cannot take on more than 1 electron, but that is enough
A greater applied force is required to move an object with a greater mass than one with a smaller mass.
True
False
Answer:
True
Explanation:
The bigger an object is, the more force you must apply to move the object. Think about it like moving a mouse compared to moving an elephant. You can't move the elephant by yourself, because you don't have enough strength or force to move it. But, you can easily pick up a mouse, because it requires less force, or strength. Hope this helped :)
Answer:
I don't know
Explanation:
sorry but I will help u next time kk
Muốn đun sôi 200g nước từ 30 độ cần cung cấp nhiệt lượng bao nhiêu :
Answer:
cần cung cấp 70 độ vì nước sôi ở 100°C
Explanation:
List two factors that compression force depends on
The magnitude (size or numerical value) and the direction.
Hope this helps!!! :)
Which element has atoms with valence electrons in a higher energy level than those of calcium (Ca)?
(1 point)
oxygen (O)
lithium (Li)
bromine (Br)
cesium (Cs)
Lithium element contains one electron therefore valence electron will be one.
The highest level of energy is due to valence electrons which are available to the atom.
The calcium has 2 valence electrons which has electrons with high energy.
These energy will be used by the electron during the chemical reaction, and they will either lose or gain valence electron.
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Answer:
calcium
Explanation:
2 electron
A car horn creates a 595 Hz tone at rest. Two cars pass on the street, each going 20.0 m/s; the first car honks. What frequency does the other car hear before they pass each other?
Doppler frequency, the other car hear before they pass each other is 668.68 Hz.
What is frequency?Frequency is the number of occurrences of a repeating event per unit of time.
What is Doppler EFFECT?The Doppler effect is the change in frequency of a wave in relation to an observer who is moving relative to the wave source.
According to the Doppler Effect, the frequency observed is
[tex]fo=fs\frac{v+v_{o} }{v-v_{s} }[/tex]
[tex]f_{o}=595\frac{343+20 }{343-20 }\\f_{o} = 668.68 Hz[/tex]
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If the force on a spring is 1 N and it stretched 0.5 m, what is the spring
constant?
A.4 N/m
B.0.2 N/m
C.2 N/m
D. 0.4 N/m
We know
[tex]\boxed{\sf Spring\:constant(K)=\dfrac{F}{x}}[/tex]
[tex]\\ \sf\longmapsto K=\dfrac{1}{0.5}[/tex]
[tex]\\ \sf\longmapsto K=2N/m[/tex]
The hydro power plant transforms one form of energy into another. However, the total amount
of energy of the water stays the same until it enters the turbine.
Explain how this statement is supported by the three column charts above.
*attached is the column charts
The hydro power plant consists of a (artificial) dam that builds gravitational potential energy, P.E. from natural flowing water sources, by locating the dam along the water path. The stored potential energy, P. is converted into kinetic energy, K.E. as the water falls from the dam, down to the turbines, located at a much lower level according to the following principle of conservation of energy equation;
Total Mechanical Energy, M.E. = The potential energy of the water, P.E. + The kinetic energy of the water, K.E. = Constant
M.E. = P.E. + K.E. = Constant
Where;
P.E. = m·g·h
K.E. = (1/2)·m·v²
m = Mass
g = The acceleration due to gravity
h = The height of the dam
v = The velocity
The charts can be explained as follows;
Given that the potential energy P.E. = m·g·h, we have that the potential energy is directly proportional to the height of the dam, and therefore, at mid height, the potential energy would be half the maximum value, and we have;
At mid height, P.E. = (1/2)·[tex]\mathbf{P.E._{max}}[/tex]
At the top of the dam, the (vertical) velocity of the water = 0, therefore, the kinetic energy = 0
Therefore, at the top of the dam, we get;
M.E. = [tex]P.E._{max}[/tex] + 0 =
M.E. = [tex]\mathbf{P.E._{max}}[/tex]
Similarly, at the bottom of the dam, the height, h = 0, therefore, being proportional to the height, P.E. = 0, and the velocity is maximum, and at the bottom, we have;
M.E. = 0 + [tex]K.E._{max}[/tex]
The first chart, water is halfway down the dam
At the halfway down therefore, we have;
P.E. = (1/2)·[tex]\mathbf{P.E._{max}}[/tex]
M.E. = [tex]P.E._{max}[/tex] = (1/2)·
∴ K.E. = [tex]P.E._{max}[/tex] - (1/2)·
Therefore the first chart, water is halfway down the dam;
Halfway, K.E. = (1/2)·[tex]\mathbf{P.E._{max}}[/tex] = P.E.
∴ K.E. = P.E. as shown on the chart
The second chart, water has reached the turbine
Water reaches the turbine at the bottom, and as explained above, we get;
M.E. = 0 + [tex]K.E._{max}[/tex]
∴ M.E.≈ [tex]K.E._{max}[/tex]
Therefore, when water has reached the turbine at the bottom of the dam, the kinetic energy is approximately proportional to the total mechanical energy as shown in the chart
The third chart, water is at the top of the dam
Here as shown above, we have;
The total mechanical energy, M.E. ≈ [tex]\mathbf{P.E._{max}}[/tex] as shown on the chart
Learn more about potential and kinetic energy here;
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define radiation explain it
Radiation is energy that comes from a source and travels through space at the speed of light. This energy has an electric field and a magnetic field associated with it, and has wave-like properties. You could also call radiation “electromagnetic waves”.
cdc
what give negative acceleration ?
Answer:
But negative acceleration means that the rate of change of velocity is negative or velocity decreases. Example: (1) When we apply brakes in a moving car, then negative acceleration acts on it and the car stops. (2) When we throw a ball upwards, then also negative acceleration acts on it.
Explanation:
If it helps you mark me as a brainleast
MATHEMATICALLY A NEGATIVE ACCELERATION MEANS YOU WILL SUBTRACT FROM THE CURRENT VALUE OF THE VELOCITY.
Two representative elements are in the same period of the periodic table. Which statement correctly describes the atoms of the two elements?(1 point)
They have the same number of electrons.
They have the same number of valence electrons.
They have valence electrons in different energy levels.
They have valence electrons in the same energy level.
Answer:
Elements in the same group have the same number of valence electrons.
When moving right across a period, the valence electrons of the main group elements increase by one.
When moving down a group, the valence electrons of the main group elements increase by one.
Elements in the same period have the same number of valence electrons.
Elements in the same period of the periodic table have valence electrons in the same energy levels.
When elements are in the same period on the periodic table, it means that they have the same number of shells.
The energy level of valence electrons in a atom depends on how far it is from the nucleus. This means that:
Valence electrons on elements in the same period will be the same distance from their nucleus They will have the same energy level as they are equally attracted to their nucleusFor instance, Boron, Carbon and Nitrogen will have valence electrons in the same energy levels.
In conclusion, elements in the same period will have valence electrons in the same energy levels.
Find out more at https://brainly.com/question/21367069.
find the expression for the displacement covered in nth or in last one second
Answer:
Snth = u + a/2 ( 2n - 1)
Explanation:
Do you need explanation based on graph, integration or other method?
A pulley system is made of 3 pulley write its velocity ratio
Almost 3 times fast than normal pulley system
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Find out the name of metals which can be obtained from the following .a) argentite b)hematite c)chalcopryite d)bauxite e)calverite
Answer:
a). Silver, Ag
b). Iron, Fe
c). Copper, Cu
d). Aluminium, Al
e). Gold, Au
Ley de Charles-.
1) En un recipiente hermético se tiene 150 ml de una sustancia gaseosa, a una temperatura de 115°C, esto como resultado de una reacción. ¿Cuál sería su volumen inicial, cuando su temperatura era de 100°C?
2) Al inicio cuando la temperatura es de 200°C, se tienen 350 ml de un gas “Y”. ¿Qué volumen se obtendrá si la temperatura se incrementa a 250°C?
Tomando en cuenta la Ley de Charles y la condiciones dentro del recipiente, tenemos las siguientes conclusiones con respecto al volumen del recipiente:
1) El volumen inicial del gas es 144.203 mililitros.
2) El volumen final del gas es 386.986 mililitros.
La Ley de Charles establece que el Volumen de un gas es directamente proporcional a su Temperatura, basados en este hecho, podemos resolver los problemas en cuestión mediante la siguiente relación matematica:
[tex]\frac{V_{1}}{T_{1}} = \frac{V_{2}}{T_{2}}[/tex] (1)
Donde:
[tex]V_{1}[/tex] - Volumen inicial, en mililitros.
[tex]V_{2}[/tex] - Volumen final, en mililitros.
[tex]T_{1}[/tex] - Temperatura inicial, en Kelvin.
[tex]T_{2}[/tex] - Temperatura final, en Kelvin.
1) Si sabemos que [tex]V_{2} = 150\,mL[/tex], [tex]T_{2} = 388.15\,K[/tex] and [tex]T_{1} = 373.15\,K[/tex], entonces el volumen inicial del gas es:
[tex]V_{1} = \frac{T_{1}}{T_{2}}\times V_{2}[/tex]
[tex]V_{1} = \frac{373.15\,K}{388.15\,K}\times 150\,mL[/tex]
[tex]V_{1} = 144.203\,mL[/tex]
El volumen inicial del gas es 144.203 mililitros.
2) Si sabemos que [tex]T_{1} = 473.15\,K[/tex], [tex]V_{1} = 350\,mL[/tex] and [tex]T_{2} = 523.15\,K[/tex], entonces el volumen final del gas es:
[tex]V_{2} = \frac{T_{2}}{T_{1}}\times V_{1}[/tex]
[tex]V_{2} = \frac{523.15\,K}{473.15\,K}\cdot 350\,mL[/tex]
[tex]V_{2} = 386.986\,mL[/tex]
El volumen final del gas es 386.986 mililitros.
He aquí una pregunta relacionada con la Ley de Charles: https://brainly.com/question/21184611
9. Which of the following is NOT a recommendation to help you succeed in this course?
Consistently and actively work in the course on a daily basis.
Wait until the end of the semester to complete all work.
Complete all assignments in a timely manner.
Contact your instructor if you have questions.
Answer:
Wait until the end of the semester to complete all work.
Explanation:
this is the obvious answer.
please mark me brainliest
Answer:
Wait until the end of the semester to complete all work
A 2.0kg object is dropped from a height of 30m.
After it drops for 2.0 seconds, what is its kinetic
energy and what is its potential energy?
(Assume no air resistance.)
Answer:
1) The kinetic energy of the object after it drops for 2.0 seconds is approximately 384.9 Joules
2) The potential energy of the object after it drops for 2.0 seconds is approximately 204 J
Explanation:
1) The given mass of the object, m = 2.0 kg
The height from which the object is dropped, h = 30 m
The kinetic energy of the object after it drops for 2.0 seconds = Required
Kinetic energy, K.E. = (1/2)·m·v²
Where;
v = The velocity of the object
The kinematic equation for finding the velocity of the object is presented as follows;
v = u + g·t
Where;
u = The initial velocity of the object = 0
g = The acceleration due to gravity of the object ≈ 9.81 m/s²
t = The time of motion of the object = 2.0 seconds
∴ The velocity after 2 seconds, v ≈ 0 + 9.81 m/s² × 2 s = 19.62 m/s
The kinetic energy, K.E. after 2 seconds as the object drops is given as follows;
[tex]K.E._{(after \ two \ seconds)}[/tex] = (1/2) × 2.0 kg × (19.62 m/s)² = 384.9444 J ≈ 384.9 J
2) The total energy, M.E. of the object at the top, h = 30 m, u = 0, is given as follows;
The total mechanical energy, M.E. = P.E. + K.E.
M.E. = m·g·h + (1/2)·m·u²
∴ M.E. = 2.0 kg × 9.81 m/s² × 30 m + 0 = 588.6 J
M.E. = 588.6 J
Given that the total mechanical energy, M.E., is constant, we have;
At 2.0 seconds, M.E. = 588.6 J , K.E. ≈ 384.9 J, P.E. = M.E. - K.E.
∴ P.E. = 588.9 J - 384.9 J ≈ 204 J
The potential energy after it drops 2.0 seconds, P.E. ≈ 204 J
A force of 150N at an angle of 60 degree to the horizontal to pull a box through a distance of 50m calculate the work done
[tex]\boxed{\sf W=Fscos\Theta}[/tex]
[tex]\\ \sf\longmapsto W=150(50)cos 60[/tex]
[tex]\\ \sf\longmapsto W=7500\times \dfrac{1}{2}[/tex]
[tex]\\ \sf\longmapsto W=3750J[/tex]
Which of the following is a vector quantity? i. Force ii. Velocity iii. Acceleration iv. All of these 5771
Option ( iv ) is the correct answer.
☛ DefinitionA vector quantity the physical quantity that has both direction as well as magnitude.
Which of the following is an exa example of a wave
Longitudinal waves
Transverse waves
Electromagnetic Waves
Water waves
Rope waves
LIght Waves
If we increase the surface area of a given surface without changing the force acting on it, then the pressure acting on it will ______ (increase/decrease/remain the same)
Answer:
Decrease
Explanation:
The pressure is the force per unit area. So, P=F/A
Thus the pressure P is inversely proportional to contact area A.
So when area increases , the pressure will be decreasing.
Give reason.
b} String roller is an example of wheel and axel .Why?
Explanation:
string roller is called an example of wheel and axel because The thin rod which needs to be turned is called the axle and the wider object fixed to the axle, on which we apply force is called the wheel.
hence the we apply force on the roller and the string gets tight.
any person who opens the door he applies
Answer:
any person who opens the door he applies pulling force
mercury is commonly used in thermometer give reasons
Answer:
hi
BECAUSE MERCURY IS USED BECAUSE IT is the only liquid available in room temperatureExplanation:
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a car moves at a speed of 40km/h. it is stopped by applying brake which produce a uniform acceleration of-0.5m/s^2. how much distance will it move before coming to stop ?
Answer:
Explanation:
We first need to convert the 40 km/h to m/s. Going by the fact that 40 has only 1 significant figure in it, 40 km/h = 10 m/s. The rest of the values are in their proper labels. We will use the equation:
[tex]v^2=v_0^2+2a[/tex]Δx where the final velocity is 0 because the car is coming to a stop at the end; the initial velocity is 10 m/s, the acceleration (or, rather, deceleration) is -.5 m/s/s, and our unknown which is displacement. Filling in:
[tex]0=(10)^2+2(-.5)[/tex]Δx and solving for Δx:
Δx = [tex]\frac{-100}{2(-.5)}[/tex] which ends up being simply that
Δx = 100 m
Give reason Pascal is a derived unit
Answer:
Pascal is a derived unit because it cannot be expressed in any physics terms, but it is an expression of fundamental quantities.
Explanation:
[tex]{ \sf{Pasacal \: ( Pa) = \frac{newtons}{metres {}^{2} } }} \\ \\ { \sf{Pasacal \: (Pa) = \frac{kg \times {ms}^{ - 2} }{ {m}^{2} } }}[/tex]
