Answer:
[tex]\mathbf{\dfrac{I(5l)}{I(l) } =10^{-8}}[/tex]
Explanation:
We are being told that the current is proportional to the tunneling coefficient[tex]I(l) = I_0 e^{-2kl}[/tex] ;
where l = distance between the tip and the surface.
Let [tex]I(l) = I_0 e^{-2kl}[/tex] ------------ equation (1)
and [tex]I(5l) = I_0 e^{-2k(5l)}[/tex] ------------ equation (2)
Dividing equation (2) by (1); we have :
[tex]\dfrac{I(5l)}{I(l) } = \dfrac{I_0 e^{-2k(5l)}}{ I_0 e^{-2kl}}[/tex]
[tex]\dfrac{I(5l)}{I(l) } =e^{-2k(5-1)l}[/tex]
[tex]\dfrac{I(5l)}{I(l) } =(e^{-2kl})^4[/tex]
where ;
[tex](e^{-2kl})[/tex] represents the transmission coefficient T = 0.01
Thus; replacing the value for 0.01;we have;
[tex]\dfrac{I(5l)}{I(l) } =0.01^4[/tex]
[tex]\mathbf{\dfrac{I(5l)}{I(l) } =10^{-8}}[/tex]
The ratio of the magnitude of the frictional force to the magnitude of the force
holding two surfaces together is called the and its UNIT is
Answer: the coefficient of friction
Explanation:
The coefficient of friction (μ (mu)) has no unit because it is a ratio of forces so the units of N (newtons, which are the units of force) cancel out.The magnitude of frictional force is [tex]\mu[/tex]N and the magnitude of the force is N. So if we take the ratio of it we will get [tex]\mu[/tex] In result.
What is the Coefficient of friction?The friction coefficient is the ratio of the normal force pressing two surfaces together to the frictional force preventing motion between them. Typically, the Greek letter is used to symbolize it, i.e., [tex]\mu[/tex]. In mathematical terms, is equal to F/N, where F represents frictional force and N represents normal force. Since both F and N are measured in units of force, the coefficient of friction is a dimensional less quantity (such as newtons or pounds).
For both static and kinetic friction, the coefficient of friction has a range of values. When an object experiences static friction, the frictional force resists any applied force, causing the object to stay at rest until the static frictional force is removed. In kinetic friction, the frictional force resists the motion of the object.
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Please help! 100 points!
What are some ways that the nitrogen cycle overlaps with or influences the oxygen and carbon cycles?
Are any of these interactions between the cycles positive?
Are any negative?
What about when the nitrogen cycle is thrown off balance by the Haber-Bosch process and others like it?
How can that influence the oxygen and carbon cycles?
Are there other cycles involved that have not been mentioned in this question?
What does this discussion suggest about the nature of the Earth as one large system?
Answer:
1.Nitrification happens when soil organisms change over ammonium into nitrate. Much of the cover between the carbon cycle and the nitrogen cycle happens within the soil, in forms conducted by soil organisms. Organisms break down supplements, construct modern compounds for their possess development, and inevitably pass on.
The second question im not sure sorry- the positive and negative one ;(
3. Many human activities have a significant impact on the nitrogen cycle. Burning fossil fuels, application of nitrogen-based fertilizers, and other activities can dramatically increase the amount of biologically available nitrogen in an ecosystem. As nitrogen makes up 78% of the atmosphere, there is no shortage of it – it just isn't in a form plants and animals can use.
4. Carbon makes its way through living things as carbon-based compounds, like vitality particles, fats and proteins, in the long run cycling its way back into the environment. Nitrogen is basically found within the air as well and enters the environments as supplements for plants. Water, nitrogen and carbon cycles. Carbon moves from the air and back by means of creatures and plants. Nitrogen moves from the environment and back by means of living beings. Water moves on, over, or underneath the surface of the Soil.
5. Carbon cycle, Nitrogen cycle, Nutrient cycle, Oxygen cycle, Phosphorus cycle, Sulfur cycle, Rock cycle, Water cycle.
6. Wind, water, and ice disintegrate and shape the arrive. Volcanic movement and seismic tremors change the scene in a sensational and frequently savage way. And on a much longer timescale, the development of earth's plates gradually reconfigures seas and landmasses. Each one of these forms plays a part within the Cold and Antarctica.
People affect the physical environment in numerous ways: overpopulation, contamination, burning fossil powers, and deforestation. Changes like these have activated climate alter, soil disintegration, destitute discuss quality, and undrinkable water. Earth's surface is the as it were territory accessible to the human race. Understanding the forms by which that environment has been made and persistently changed is critical to decide the causes of natural degradation.
A box that has a mass of 80 kg slides down a ramp with a 30 degree angle. The free-body diagram shows the forces acting on the box. A block is shown on a 30-degree incline with a free body diagram drawn on the block with 2 force vectors. The first vector is pointing away from the surface of the incline and perpendicular to the surface, labeled F Subscript N Baseline. The second vector is pointing straight down to the center of the earth, labeled F Subscript g Baseline. Ignoring friction and air resistance, what is the acceleration of the box, to the nearest tenth? 0.5 m/s2 4.9 m/s2 8.5 m/s2 9.8 m/s2
HOW TO DO IT
Answer:
B. 4.9 m/[tex]s^{2}[/tex]
Explanation:
The parallel vector, [tex]F_{g}[/tex], make the box to accelerate down the plane due to the presence of an unbalanced force.
The perpendicular component of the force will balance the normal force because the box can not accelerate perpendicularly to the plane.
i.e [tex]F_{N}[/tex] = [tex]F_{g}[/tex]
Since the box slides down the ramp, neglecting friction and air resistance;
[tex]F_{g}[/tex] = ma
mg Sinθ = ma
But; m = 80 kg, θ = [tex]30^{0}[/tex], g = 9.8 m/[tex]s^{2}[/tex]
80 × 9.8 × Sin [tex]30^{0}[/tex] = 80 × a
784 × 0.5 = 80 a
392 = 80 a
a = [tex]\frac{392}{80}[/tex]
= 4.9
Thus, the box accelerates down the ramp at 4.9 m/[tex]s^{2}[/tex].
Answer:
b
Explanation:
b
Which of these objects has the largest volume?
Answer:
The balloon
Explanation:
Since there are 100 cm or 1000 mm in a meter, you can rewrite the dimensions in the following way:
A cube of metal with a volume of 10,000 mm^3
A spherical balloon with a volume of 50,000,000 mm^3
A sample of water with a volume of 1,000 mm^3
Therefore, the balloon clearly has the most volume. Hope this helps!
Answer:
spherical baloon
Explanation:
change all the measurements to be one I.e convert the m³ and mm³ to cm³
2)1m³=1000000cm³ what about 0.05m³
balloon =50000cm³
3)1cm3=1000mm³
water=1cm³
1)cube=10cm³ so which is the greatest
=spherical baloon
10) Um viajante, ao desembarcar no aeroporto de Londres, observou que o valor da temperatura do ambiente na escala Fahrenheit é o quíntuplo do valor da temperatura na escala Celsius. Calcule essa temperatura
Answer:
The observed temperature was 10º Celsius or 50º Fahrenheit.
Explanation:
The traveler observed that the temperature in Fahrenheit is five times the value of the temperature in Celsius, therefore:
[tex]F = 5*C[/tex]
A Fahrenheit temperature relates to a Celsius one by the following expression:
[tex]F = \frac{9}{5}*C + 32[/tex]
Using the second expression on the first, we can solve for the temperature in Celsius, this is done below:
[tex]\frac{9}{5}*C + 32 = 5*C\\\frac{9}{5}*C - 5*C = -32\\\frac{9*C - 25*C}{5} = -32\\\frac{-16*C}{5} = -32\\-16*C = -32*5\\-16*C = -160\\C = \frac{-160}{-16} = 10\º\text{C}\\F = 5*C = 5*10 = 50\º\text{F}[/tex]
The observed temperature was 10º Celsius or 50º Fahrenheit.
Which statements best describe X-rays?
Answer:x rays are electromagnetic waves.
x rays are transverse waves
x rays travel at the speed of light
Explanation:
what activities belong at the top of the physical activity pyramid
Answer: Cut down on watching tv, sitting down for more than 30 minutes at a time, and playing video games.
Explanation:
What is the centripetal force of an object undergoing uniform circular motion when its radius is doubled and its speed remains constant?
A.
the same as before
B.
twice as great as before
C.
half as great as before
D.
four times as great as before
Answer:
C
Explanation:
Now the centripetal force is that force that keeps the object on course along the circle;
This is expressed mathematically as ;
F = mv^2/ r
Where F - centripetal force
m- mass of the object
v- velocity of the object
r- raduis
Note from the expression as r increases F decreases so if v and the mass is constant if r doubles F will reduce by half.
Answer:
C. half as great as before
Explanation:
Why would you expect sodium (Na) to react strongly with chlorine?
Answer:
Na is a alkaline metal, it can very easy give an electron, and form positive ion. Cl is a very strong non-metal(halogen), and it is able to take electron, and form negative ion. Positive and negative ion can attract to each other and form ionic bond.
A frisbee is flying through the air. Which forces are acting on it (choose 3)
Answer:
The force acting on it is lift
A German scientist, George Ohm, discovered the relationship between current, voltage, and resistance. This became known as Ohm's law. According to Ohm’s law, if V is voltage, I is current, and R is resistance, their relationship is expressed by the equation
Answer:
I=V/R is the formula for ohm's law .
Explanation: I=V/R is the formula for ohm's law
Answer:
I= V/R
Explanation:
The equation, i = v/r, tells us that the current, i, flowing through a circuit is directly proportional to the voltage, v, and inversely proportional to the resistance, r. (Study.com)
calculate the pressure exerted by a man having mass 50 kg standing on one feet having area 500cm2
Answer:
9800 Pa
Explanation:
Data: pressure-?
Force- mass ×acceleration
= 50× 9.8m/s^2
=490N
Area= 500cm^2=0.05m^2
pressure= force/ area
p=F/A
P= (490N)/( 0.05m^2)
=9800 Pa
Which equations could be used as is, or rearranged to calculate for frequency of a wave?
Answer:
frequency = wavelength over speed. f. speed = wavelength x frequency
Explanation:
it is on google
Answer:wavelength=speed/frequency
Explanation:
Can someone explain what ice jacking is and how it can cause structures to fail?
Answer: Rock slope failures can occur due to the presence of water; ice jacking occurs when water between joint or fissure surfaces freezes and expands. This type of failure is progressive, resulting in incremental weakening over time, often requiring several cycles before failure. Ice jacking is one form of rock erosion.
An object is placed at 1.5 m from a convex lens with a focal length of 1.0 m.
a. Use the thin lens equation to determine the image distance from the lens.
b. If the object height is 2.0 m, what is the image height?
c. Is the image real or virtual? Is the image inverted or upright?
Drag each tile to the correct box. Arrange the steps in order to describe what happens to a gas when it cools. The particles of gas move slower. The gas changes to a liquid. The gas loses thermal energy. The space between the gas particles decreases. ↓ ↓ ↓
Answer:
Ok, as the gas starts to cool down, the kinetic energy of the particles starts to decrease, so the first thing that happens is:
"the gas loses thermal energy" (as the gas cools down, the temperature decreases, so it loses thermal energy)
Now, the kinetic energy must decrease, so now:
"the particles of gas move slower".
Then, as the particles start to move slower, they start to get closer to eachother, then we have:
"The space between the gas particles decreases."
As the particles start to get close to eachother, the density of the gas starts to increase, until a point where we get to the condensation point, here we have a change of phase and the gas changes to a liquid, so here we have:
"The gas changes to a liquid."
Answer:
a
Explanation:
A piano with a mass of 130 kg is lifted 10m above the ground in 5 s by a crane.
What is the power used by the crane
[tex]power = 2548 \: watt \\ solution \\ mass = 130 \: kg \\ distance = 10m \\ time = 5 \: sec \\ power = \frac{w}{t} \\ \: \: \: \: \: \: \: \: \: \: = \frac{f \times d}{t} \\ \: \: \: \: \: \: \: \: = \: \frac{m \times g \times d}{t} \\ \: \: \: \: \: \: \: \: \: = \frac{130 \times 9.8 \times 10}{5} \\ \: \: \: \: \: \: \: \: = \frac{12740}{5} \\ \: \: \: \: \: = 2548 \: watt \\ hope \: it \: helps[/tex]
You apply a force of 54 N to a car jack in order to change a tire. Each "Crank" of the jack is exerted over a distance of
64 cm. What is the work input on the car jack? (Hint: 1m = 100 cm)
Step # 1
Step #2
Step #3
Explanation:
Work = force × distance
W = (54 N) (0.64 m)
W ≈ 35 J
Two people try to lift a heavy box. Jack pulls upward with a 100-newton
force. Jill pulls upward with a 50-newton force, but neither person moves the
box.
Compare the amount of work done on the box by Jack and Jill.
OA) Jack did twice as much work as Jill.
OB) Jack did fifty times more work than Jill.
OC) Jack and Jill did the same amount of work.
Answer:
A ( Jack did twice as much work as Jill
Explanation:
A helium ion of mass 4m and charge 2e is accelerated from rest through a potential difference V in vacuum. Its final speed will be
Answer:
Final Velocity = √(eV/m)
Explanation:
The Workdone, W, in accelerating a charge, 2e, through a potential difference, V is given as a product of the charge and the potential difference
W = (2e) × V = 2eV
And this work is equal to change in kinetic energy
W = Δ(kinetic energy) = ΔK.E
But since the charge starts from rest, initial velocity = 0 and initial kinetic energy = 0
ΔK.E = ½ × (mass) × (final velocity)²
(Velocity)² = (2×ΔK.E)/(mass)
Velocity = √[(2×ΔK.E)/(mass)]
ΔK.E = W = 2eV
mass = 4m
Final Velocity = √[(2×W)/(4m)]
Final Velocity = √[(2×2eV)/4m]
Final Velocity = √(4eV/4m)
Final Velocity = √(eV/m)
Hope this Helps!!!
What is the effect of gravity on a falling object?
Answer:
When objects fall to the ground, gravity causes them to accelerate.
For a moving object, the force acting on the object varies directly with the objects acceleration. When a force of 24N acts on a certain object, the acceleration of the object is 3m/s^2. If the acceleration of the object becomes 10m/s^2, what is the force
Answer:
80 N
Explanation:
From the question,
F = ma .......................... Equation 1
Where F = Force, m = mass of the object, a = acceleration of the object.
make m the subject of the equation
m = F/a.................... Equation 2
Given: F = 24 N, a = 3 m/s²
Substitute into equation 2
m = 24/3
m = 8 kg.
If the acceleration of the object becomes 10 m/s²,
Substitute into equation 1
F = 10(8)
F = 80 N.
Un gas se encuentra a una presión constante y a una temperatura de 30°C. Si la temperatura aumenta a 45°C, su presión varía a 6 atm. ¿Cuál era la presión inicial del gas? Transforma los °C en °K.
Answer:
P1 = 5.76 atm
Explanation:
To find the initial pressure of the gas you use the equation for ideal gases, for both temperatures and pressures:
[tex]P_1V=nRT_1\\\\P_2V=nRT_2\\\\[/tex]
T1: initial temperature = 30°C = 303.15K
T2: final temperature = 45°C = 318.15K
P1: initial pressure = ?
P2: final pressure = 6atm
n: number of moles
R: ideal gas constant
The number of moles and R are constant, you can dive the first equation into the second and solve for P1:
[tex]\frac{P_1V}{P_2V}=\frac{nRT_1}{nRT_2}\\\\\frac{P_1}{P_2}=\frac{T_1}{T_2}[/tex]
[tex]P_1=\frac{T_1P_2}{T_2}[/tex]
Finally, you replace the values of T1, P2 and T2:
[tex]P_1=\frac{(303.15K)(6atm)}{318.15K}=5.71atm[/tex]
hence, the initial pressure of the gas was 5.71 atm
In a circuit, energy is transferred to a charge.
Where is this energy transferred from?
Answer:
Electric current.
Explanation:
The energy result from electric current resulting from potential differences between terminals which form an Electric circuit. This energy could come from different sources like chemical, wind, light
An electric circuit is one where there is movement of electrons;this electrons acquire charge which is energy. The electrons flow due to a potential difference; you have heard water flows from a higher position to a lower one freely. The highest height is said to be at higher potential and the lower point low potential.
So it's the same with electrons.
The formular for energy on charge is Q= I × t where I is electric current and t is time.
Investigator Robbins is called to the scene of a robbery. The officer on the scene thinks that the suspect entered the home from the garage. As Investigator Robbins checks over the house, he does not find any evidence of forced entry. He cannot find any physical evidence near the garage door at all. There is a window open above the kitchen sink and footprints in the mud under the window outside. Based on his examination, what conclusion might Investigator Robbins make?
1. The officer was correct; the garage was the point of entry.
2. There is no evidence to indicate that anyone entered the home.
3. The officer's conclusion was mistaken, and a suspect may have entered through the window.
4. The garage was the point of entry, but the window was the escape route.
Answer:
3
Explanation:
Since the evidence found points to the window on investigation remember there was a foot print below the window as well as the window been opened.
What are some potential sources of error in the
experiment that is described in the article?
Answer: experimental design
the accuracy of data-collecting devices
human error
bias in selecting samples
incorrect data analysis
incorrect treatment of the control group
Explanation:
Instrumental, environmental, procedural, and human errors are frequent causes. Depending on how they affect the outcomes, each of these errors can either be random or systematic.
What are Experimental Error?The discrepancy between a measured value and its true value is known as experimental error. In other words, the error or inaccuracies are what prevent us from perceiving a measurement that is 100 percent accurate.
Every measurement has some degree of experimental error, which is fairly common. Due to the widespread belief that some degree of error is inherent to the scientific method, it is not typically seen as a "mistake" in the classic sense.
However, scientists can reduce error and obtain results that are more accurate by embracing and comprehending the ways that experimental error can affect any scientific operation.
The potential sources of error in experiment are Instrumental, environmental, procedural, and human errors.
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Q1: A step-up transformer has 80 turns on its primary coil and 1200 turns on its secondary coil. The
primary circuit is supplied with an alternating current at 120 V.
a) What voltage is being applied across the secondary circuit?
b) The current in the secondary circuit is 2.0 A. What current is in the primary circuit?
c) What are the power input and output of the transformer?
Answer:
a. 1.8 kV b. 30 A c. power input = 3.6 kW, power output = 3.6 kW
Explanation:
a. Since turns ratio N₁/N₂ = V₁/V₂ where N₁ = number of turns of primary coil = 80 turns, N₂ = number of turns of secondary coil = 1200 turns, V₁ = voltage in primary circuit = 120 V and V₂ = voltage in secondary circuit = unknown
So, V₂ = N₂V₁/N₁
= 1200 × 120 V/80
= 1800 V
= 1.8 kV
b. Also, N₁/N₂ = I₂/I₁ where I₁ = current in primary circuit = unknown and I₂ = current in secondary circuit = 2.0 A
So, I₁ = N₂I₂/N₁
= 1200 × 2.0 A/80
= 30 A
c. The power input of the transformer P₁ = I₁V₁
= 30 A × 120 V
= 3600 W
= 3.6 kW
The power output of the transformer P₂ = I₂V₂
= 2 A × 1800 V
= 3600 W
= 3.6 kW
a) The voltage applied across the secondary circuit is 1.8 kV
b) The current in the primary circuit is 30 A
c) The power input and output of the transformer are 3.6 kW and 3.6 kW.
What is transformer?A transformer transfers electric energy from one AC circuit to one or more other circuits, either stepping up or stepping down the voltage.
a) Turns ratio N₁/N₂ = V₁/V₂ where N₁ = number of turns of primary coil = 80 turns, N₂ = number of turns of secondary coil = 1200 turns, V₁ = voltage in primary circuit = 120 V
Substitute the values and we get the voltage in secondary circuit is
V₂ = N₂V₁/N₁
V₂ = 1200 × 120 V/80
V₂ = 1800 V
V₂ = 1.8 kV
Thus, the voltage applied across the secondary circuit is 1.8 kV
b) Turn ratio also represented as N₁/N₂ = I₂/I₁ where I₂ is the current in secondary circuit = 2.0 A
Put the values, we have current in primary circuit is
I₁ = N₂I₂/N₁
I₁ = 1200 × 2.0 A/80
I₁ = 30 A
Thus, the current in the primary circuit is 30 A
c) The power input of the transformer P₁ = I₁V₁
P₁ = 30 A × 120 V
P₁ = 3600 W
P₁ = 3.6 kW
The power output of the transformer P₂ = I₂V₂
P₂= 2 A × 1800 V
P₂= 3600 W
P₂= 3.6 kW
The power input and output of the transformer are 3.6 kW and 3.6 kW.
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A soccer player kicks a ball with an initial velocity of 10m/s at an angle of 30 degrees above the horizontal. Find the; a) magnitude of the horizontal component b) Vertical component c) The magnitude of the vector.
Answer:
a) V₀ₓ = 8.66 m/s
b) V₀y = 5 m/s
c) Magnitude of velocity vector = 10 m/s
Explanation:
a)
The magnitude of the horizontal component of launch velocity can easily be given by the following formula:
V₀ₓ = V₀ Cos θ
where,
V₀ₓ = horizontal component of velocity = ?
V₀ = Launch Velocity = 10 m/s
θ = Launch Angle of the ball with the horizontal = 30°
Therefore,
V₀ₓ = (10 m/s)(Cos 30°)
V₀ₓ = 8.66 m/s
b)
The magnitude of the vertical component of launch velocity can easily be given by the following formula:
V₀y = V₀ Sin θ
where,
V₀y = vertical component of velocity = ?
V₀ = Launch Velocity = 10 m/s
θ = Launch Angle of the ball with the horizontal = 30°
Therefore,
V₀y = (10 m/s)(Sin 30°)
V₀y = 5 m/s
c)
The magnitude of the velocity vector will be equal to the resultant velocity or net velocity, which is 10 m/s.
Magnitude of Velocity Vector = 10 m/s
a linear function has the same y-intercept as x + 4y equals 16 and it's graph contains the point (4,5). Find the slope of the linear function.
Answer: [tex]\bold{\text{Slope (m)}=\dfrac{1}{4}}[/tex]
Explanation:
A linear equation is of the form: y = mx + b where
m is the slopeb is the y-intercept (where it crosses the y-axis)x + 4y = 16
4y = -x + 16
[tex]y = -\dfrac{1}{4}x+\dfrac{16}{4}[/tex]
[tex]y=-\dfrac{1}{4}x+4[/tex]
The y-intercept (b) = 4
Next, find the slope given point (4, 5) and b = 4
[tex]y=mx+b\\\\5=m(4)+4\\\\1=4m\\\\\dfrac{1}{4}=m\\\\\\\\\large\boxed{Slope (m)=\dfrac{1}{4}}[/tex]
Q2 : Water waves in a shallow dish are 6cm long. At one point water moves up and down at a rate of 4.8 oscillation per second. What is the speed of water waves? What is the period of water waves? What is the frequency of water waves?
Answer:
v = 0.3 ms⁻¹
Frequency = 4.8 Hz
T = 0.21 sec
Explanation:
The rate of oscillation is 4.8 oscillation/second
Let's see frequency's definition " no. of vibration/oscillation per unit time"
So,
Frequency = 4.8 Hz
Now
Time period is the reciprocal of frequency
T = 1/f
T = 1/4.8
T = 0.21 sec
Now
Using formula
v = f λ
f = 4.8 Hz , λ = 6 cm (But we need to convert it in a standard form)
So, λ = 0.06 m
Putting in formula
v = (4.8)(0.06)
v = 0.3 ms⁻¹