Answer:
Coording metal is a physical change.
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?
any person who opens the door he applies
Answer:
any person who opens the door he applies pulling force
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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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
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
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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]
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
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.
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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
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
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
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.
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:
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
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]
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
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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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:
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MATHEMATICALLY A NEGATIVE ACCELERATION MEANS YOU WILL SUBTRACT FROM THE CURRENT VALUE OF THE VELOCITY.
2. a. in which principle does simple machine works?
Answer:
A simple machine uses a single applied force to do work against a single load force
Ignoring the friction losses. The work done on the load is equal to the work done with the applied energy. The machine can increase the amount of output power, with a corresponding drop in the distance transported by the load.
please answer me fast
Answer: i think c
Explanation:QA: “What is ordinary glass made of ?”
Glass is mostly silica, or silicon dioxide, present as quartz in many types of sand. Pure silica forms a highly transparent glass, but has a very high melting or softening temperature, around 1700°C. Even at such high temperatures it is highly viscous and difficult to work. Its use is largely confined to applications requiring high transparency to ultra-violet and infra-red radiation, stability at elevated temperatures or low thermal expansion coefficient.
“Ordinary glass” windows and drinking vessels are typically made from soda-lime glass, containing silica with around 25% sodium, calcium and other oxides, which together reduce the softening temperature to roughly 500–600°C
what weight is recorded by a scale when it is placed inside a lift which is in free fall? Enplain.
Answer:
Explanation:
There is no pressure of your feet on the scales, and no pressure of the floor on the scales, so the scales will read zero*. Hence, your weight, in a freely falling lift is zero
To what height, h, would the pendulum bob rise after a single swing if it was being released from the height of 0.80 m
Answer:
0.80 m
Explanation:
Neglecting friction, the total mechanical energy of the pendulum is constant.
E = K + U where K = kinetic energy and U = potential energy.
At its release point of 0.80 m, the pendulum bob has a mechanical energy which is equal to its potential energy, since, its initial kinetic energy is zero. By the time the bob swings to the other end, it has a mechanical energy equal to it initial potential energy since total energy is conserved.
Neglecting friction, the pendulum bob would swing back to its original height of 0.80 m since the total mechanical energy is conserved and at its highest point, it is purely potential energy.
So, the height the pendulum bob swings to after release from a height of 0.80 m neglecting fiction is 0.80 m.
Current is the movement of positive charges called electrons.
A. True
B. False
help pls <33
Answer:
False -> negative charge
Answer:
false
Explanation: electrons are negative charges
protons are positive charges
good morning how ya'll doing today
Answer:
good
Explanation:
Answer:
fine
Explanation:
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A scientist studies how air blowing on plants affects their growth. He uses fans to create different amounts of wind and measures the growth of the plants. What would make this experiment more repeatable?
Answer:D.Keeping track of the exact amount of wind on each plant
Which of the following is required for photosynthesis to take place?
a.
sugar
b.
oxygen
c.
ATP
d.
water
Please select the best answer from the choices provided
A
B
C
D
please answer as quickly as possible
Answer:
D. water
Explanation:
sugar ( glucose ) and oxygen are bi-products
Answer:
(d) water
Explanation:
water is required for photosynthesis to take place .
sugar , oxygen , ATP are not required to take place in photosynthesis.
during a journey, a car travels at 40 km in 2.5 hours, next 62 km in 3 hours, then took a break for 30 minutes, again travelled the last 120 km in 3.2 hours. calculate the average speed of the car during the journey.
Why does a ship float on water when it weighs about 100tones and why a stone of less than a kg sinks
Answer with Explanation:
Let me answer this in a simple way, since the density of stone is greater than that of water, the stone sinks as the weight of the stone is greater than the weight of water displaced by it. But the ship is designed in such a way that the relative density of the ship always becomes less than that of water. Therefore, the weight of the water displaced becomes equal to the total weight of the ship and thus it floats.
There are many other ways to explain this but this should give you the general idea.
what is the direction of magnetic lines of force outside the magnet
please mark me as brainiest p
Explanation:
Magnetic lines of force are closed curves. C) Outside the magnet their direction is from north pole to south pole and inside the magnet these are from south to north pole.
what is equal to 1 hector area
Answer:
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