Answer:
Newton' second law and third law describes the situation.
Explanation:
According to the Newton's second law, the force applied on a body is proportional to the rate of change of momentum of the body.
According to the Newton's third law, for every action there is an equal and opposite reaction.
When ice skater pushes harder means more force is applied so he moves fast and more be the action force more be the reaction force.
Thus, Newton' second law and third law describes the situation.
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 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 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
how is pressure and density related?
Answer:
Density is directly proportional to pressure
Explanation:
As pressure increases (with constant temperature), density also increases.
Density is inversely proportional to temperature.
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
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 plane mirror produces a _____.
virtual image
refracted image
real image
Answer:
Explanation:
A plane mirror is the kind you look into when you look into a "regular" mirror. The image you see is right-side-up. These images are virtual. Real images are always upside down and are made by mirrors that are "parabolic" in shape. Virtual images are always right-side-up.
Q2.
1.0 kg of ice at -10°C is added to 10 g of water at 0°C.
(a)
Find the final temperature of the mixture. (The specific latent heat of fusion of
ice is 336 J/g and the specific heat capacity of ice is 2000 J kg K-1)
Please help
Answer:
gsbddgshdhsghhdhdhvvs
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]
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
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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In order to find the resultant of two vectors we must use the pythagoran therom, a +b2-2. Where the crepresents the resultant vector
Answer:
Furthermore, the Pythagorean theorem works when the two added vectors are at right angles to one another - such as for adding a north vector and an east vector.
convert 12 kg into gram
Answer:
12000gram
Explanation:
1kg=1000gram
so, 12kg=12x1000
12kg=12000gram
Given amount=12kg
[tex]\boxed{\sf 1kg=1000g}[/tex]
[tex]\\ \sf\longmapsto 12kg=12(1000)[/tex]
[tex]\\ \sf\longmapsto 12kg=12000g[/tex]
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
Which of the following is an exa example of a wave
Longitudinal waves
Transverse waves
Electromagnetic Waves
Water waves
Rope waves
LIght Waves
A 6 kg object's Ug increases by 150 J. What was its change in height?
Please help I don’t understand this and fast please
Answer:
2.5 m
Explanation:
Potential energy is the energy stored in an object as a result of its position relative to other objects
The change in potential energy is given by:
ΔPE = mgh;
where ΔPE is the change in potential energy, m is the mass if the object, g is the acceleration due to gravity and h is the change in height of the object.
Hence given that g = 10 m/s², ΔPE = 150 J, m = 6 kg, hence:
ΔPE = mgh
150 = 6 * 10 * h
150 = 60h
h = 2.5 m
Hence the change in height is 2.5 m
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.
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
any person who opens the door he applies
Answer:
any person who opens the door he applies pulling force
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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state and prove Newton's second law of motion
Answer:
HOPE IT HELP YOU A LOT :)
I prove it also .
Answer:
Newtons Second law of motion states that"The rate of change of momentum is directly proportional to the force applied"
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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Which solution has the greatest number of hydrogen ions?
blood, pH = 7.2
lemon juice, pH = 2
soda, pH = 3.5
bleach, pH = 13.5
Answer:
lemon
Explanation:
the lower the number the hier hydrogen ions
Answer: B
Explanation:
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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3 An un calibrated mercury in glass thermometer immersed in melting ice. The length of the mercury thread is 25 mm when the thermometer immersed in steam from pure water boiling under a pressure of 1 atmosphere the length of the thread is 200 mm what is the temperature in degree centigrade when the length of the thread is 95mm.
Answer:
25 mm = 0 deg C
200 mm = 100 deg C
200 - 25 = 175 = change in thread per 100 deg C
95 - 25 = 70 mm - change in thread from 0 deg C
70 / 175 * 100 = 40 deg C final temperature at 95 mm
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?
Which of the following is occurring while a satellite is in orbit around Earth? O It is continuously pulling away from Earth It is continuously falling toward the surface of Earth. It stays in a constant speed orbit where it was oriented from the start. It stays in the same orbit orientation traveling at variable speeds.
AnswerIt is continuously falling towards the surface of the earth
Explanation:
since gravity from earth is the thing that keeps it constantly in orbit
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.
For problems 2-3, a Ferrari accelerates from 0-60.0 miles per hour in 2.50 seconds.
2. What is its final speed, in m/s?
a 5.6 m/s
b. 13 m/s
c. 26.8 m/s
d. 1608 m/s
0-60.0 per near
2.50 seconds
3. What is its average acceleration?
a. 24.0 m/s
b. 10.7 m/s2
c. 38.6 m/s2
d. 13 m/s
Answer:
Explanation:
The first part of this question is simply asking us to convert the speed from miles per hour to meters per second:
[tex]60.0\frac{mi}{hr}*\frac{1hr}{3600sec}*\frac{1609.34m}{1mi}=26.8\frac{m}{s}[/tex] choice C.
The next part wants us to use the equation for acceleration and find the acceleration:
[tex]a=\frac{v-v_0}{t}[/tex] where v is final velocity, v0 is initial velocity, and t is time in seconds (which was one of the reasons we had to convert the initial velocity from 60.0 mph to m/s):
[tex]a=\frac{26.8-0}{2.5}[/tex] and
a = 10.7 m/s/s, choice B.
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
