The shortest possible distance in which she catches up with the man is 129.7 m.
The given parameters:
speed of the man, v₁ = 40 km/hr
speed of the woman, v₂ = 70 km/hr
time when the woman started moving, t₁ = 5 seconds
To find:
the shortest distance when she catches up with the manConvert the given speed in km/h to m/s
3.6 km/h = 1 m/s40 km/h = 40/3.6 = 11.11 m/s70 km/h = 70/3.6 = 19.44 m/sCalculate the distance moved by the man before she started following him.
Distance moved by the man = speed x time
= 11.11 m/s x 5 s
= 55.55 m
Let the time the woman catches up with the man = t
Apply the following simple principle to calculate the time.
The man is moving forward and the woman is moving forward to close the gap between them, thus both speeds are working against each other.
[tex](v_2-v_1)t = 55.55 \ m[/tex]
the difference in the speed is because they are working against each other.[tex](19.44 - 11.11)t = 55.55\\\\8.33t = 55.55\\\\t = \frac{55.55}{8.33} \\\\t = 6.67 \ s[/tex]
The time when the woman catches up with the man = 6.67 s
The shortest distance at which the woman catches up with the man is calculated as;
Shortest distance = woman's speed x time when she catches up
= 19.44 m/s x 6.67 s
= 129.7 m
Thus, the shortest possible distance in which she catches up with the man is 129.7 m.
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9. Which arrow or arrows indicate a process that cycles carbon from
living or nonliving organisms? Describe the process or processes
you selected. Arrow |
10. Which arrow or arrows represent reactions that demonstrate a
conservation of mass and energy? Explain your answer.
Answer:
arrow E represents cycling of carbon from living organisms to non-living organisms. this is because it is showing conversion of a carbon from the dead tree to fossil fuel.
________________________________________________________
Darkspirit :)
Give reason
It is more difficult to climb a vertical slope than a slanted slope because
Answer:
because in vertical slope force of gravity is more than compared to slanted slope
Answer:
because gravity is always pulling objects down so when you climb upward gravity weighs you down, you have to use effort to move yourself in the opposite direction that gravity is pulling you that is why it is harder to climb up a slope.
A:10i - 2j -4k and B: i +7j - k. Determine |A-B|
A - B = (10i - 2j - 4k) - (i + 7j - k)
A - B = 9i - 9j - 3k
|A - B| = √(9² + (-9)² + (-3)²) = √189 = 3√19
Lithium's atomic number is 3. How many electrons does a neutral lithium atom have? explain.
Answer:
It has 3 electrons
Explanation:
Neutral atom has an overall charge of zero.
Since atomic number is 3, it has 3 protons [ positive charges ]. So, to be neutral, the atom must have 3 electrons [ negative charges ] to cancel out the positive charge.
Calculus-based Physics I, can someone explain this to me?
My apologies for the broadness of my question. I especially don't understand the notation being used here, but I know this is about data collection, specifically standard deviation and standard error. I mostly need help with the data collection of multiple variables, the formulae for standard deviation and standard error make no sense to me.
I could also use some examples.
2: For a sample of data [tex]x_1,x_2,\ldots,x_N[/tex], the mean of this sample denoted by [tex]\overline x[/tex] is the sum of the data divided by the number of data points,
[tex]\overline x = \dfrac{x_1+x_2+\cdots+x_N}N = \displaystyle\frac1N\sum_{i=1}^N x_i[/tex]
As an example, consider [tex]x_1=-1[/tex], [tex]x_2=1[/tex], and [tex]x_3=3[/tex]. Then
[tex]\overline x = \dfrac{-1+1+3}3 = 1[/tex]
3: Standard deviation is a measure of how dispersed a given data sample is relative to the mean. Consult the plot: for a normal distribution, approximately 68% of it lies within 1 standard deviation of the mean, approx. 95% within 2 standard deviations, and approx. 99.7% within 3 standard deviations.
For instance, if the data is pulled from a normally distributed population with mean 0 and standard deviation 1, if you were to randomly select any data from the population, then 68% of the time it will fall in the range (-1, 1); 95% of the time it will fall within (-2, 2); 99.7% of the time it fall within (-3, 3).
To compute the standard deviation for a sample, for each [tex]x_i[/tex] in [tex]x_1,x_2,\ldots,x_N[/tex], you
• take the difference between [tex]x_i[/tex] and the mean [tex]\overline x[/tex]
• square this difference
• sum all the squared differences
• divide the sum by N - 1 (for a sample) or N (for a population)
• take the square root
Here the standard deviation is denoted [tex]\sigma^x_{N-1}[/tex], which I would read as "the sample standard deviation of the data x" - sample because of the N - 1 subscript.
Continuing with the previous example, we'd have
[tex]\sigma^x_{N-1} = \displaystyle \sqrt{\frac{\left(-1-1\right)^2+\left(1-1\right)^2+\left(3-1\right)^2}{3-1}} = \sqrt4 = 2[/tex]
4: Not much more to say here, the standard error is basically a measure of how accurate a given estimate is about the population based on the sample data. It's analogous to uncertainty in measuring length with a ruler, for instance.
In our example,
[tex]\alpha^x = \dfrac2{\sqrt3}[/tex]
5: If x, y, and z are random variables, then I suppose ρ is meant to denote a function of these random variables (so that ρ itself is just another random variable). For instance, you could have ρ = x + 3y - 2z. Then [tex]\overline\rho[/tex] is the sample mean of ρ.
I'm not entirely sure about the notation [tex]x(\overline x,\sigma^x_{N-1},\alpha^x)[/tex], but I suspect it's just referring to sample x with mean [tex]\overline x[/tex] and standard deviation [tex]\sigma^x_{N-1}[/tex] with standard error [tex]\alpha^x[/tex].
∆ρ is just the differential of ρ, essentially capturing how ρ changes with respect to small changes in x, y, and z. The expression you see here follows from the chain rule for differentiation.
The formula you see for [tex]\sigma^\rho_{N-1}[/tex] is the sample standard deviation of ρ. Think of ∆ρ as a vector with 3 components. Then [tex]\sigma^\rho_{N-1}[/tex] is the magnitude of this vector.
Similarly, [tex]\alpha^\rho[/tex] is the standard error for ρ, and corresponds to the magnitude of the vector whose components are the standard errors of x, y, and z.
In order for these statistics to make sense, each of x, y, and z must be samples of the same number of data. Say we take x as before [tex](x_1=-1,x_2=1,x_3=3)[/tex], along with [tex]y_1=0,y_2=4,y_3=-2[/tex] and [tex]z_1=-3,z_2=\frac12,z_3=10[/tex]. Suppose ρ = x + 3y - 2z. Then
• the sample means of y and z :
[tex]\overline y = \dfrac{0+4-2}3 = \dfrac23 \\\\ \overline z = \dfrac{-3+\frac12+10}3 = \dfrac52[/tex]
• the standard deviations of y and z :
[tex]\sigma^y_{N-1} = \sqrt{\dfrac{\left(0-\frac23\right)^2+\left(4-\frac23\right)^2+\left(2-\frac23\right)^2}{3-1}} = 2\sqrt{\dfrac73} \approx 3.06\\\\ \sigma^z_{N-1} = \sqrt{\dfrac{\left(-3-\frac52\right)^2+\left(\frac12-\frac52\right)^2+\left(10-\frac52\right)^2}{3-1}} = \dfrac{\sqrt{181}}2 \approx 6.73[/tex]
• the values of ρ :
[tex]\rho_1 = x_1+3y_1-2z_1 = -1+2\times0-2\times(-3) = 5 \\\\ \rho_2 = x_2+3y_2-2z_2 = 1+3\times4-2\times\dfrac12=12 \\\\ \rho_3 = x_3+3y_3-2z_3 = 3+3\times(-2)-2\times10 = -23[/tex]
• the sample mean of ρ :
[tex]\overline\rho = \dfrac{5+12-23}3 = -2[/tex]
• by the chain rule,
[tex]\Delta\rho = \Delta x+3\Delta y-2\Delta z[/tex]
so the standard deviation of ρ :
[tex]\sigma^\rho_{N-1} = \sqrt{\left(\sigma^x_{N-1}\right)^2 + \left(3\sigma^y_{N-1}\right)^2 + \left(-2\sigma^z_{N-1}\right)^2} \\\\\sigma^\rho_{N-1}= \sqrt{2^2 + 9\left(2\sqrt{\dfrac73}\right)^2 + 4\left(\dfrac{\sqrt{181}}2\right)^2} = \dfrac12\sqrt{\dfrac{703}3} \approx 7.65[/tex]
• the standard errors of y and z :
[tex]\alpha^y = \dfrac{2\sqrt{\frac73}}{\sqrt3} = \dfrac23\sqrt7 \approx 1.76 \\\\ \alpha^z = \dfrac{\frac{\sqrt{181}}2}{\sqrt3} = \dfrac12\sqrt{\dfrac{181}3} \approx 3.88[/tex]
• the standard error of ρ :
[tex]\alpha^\rho=\sqrt{\left(\alpha^x\right)^2+\left(3\alpha^y\right)^2+\left(-2\alpha^z\right)^2}\\\\\alpha^\rho=\sqrt{\left(\dfrac2{\sqrt3}\right)^2+9\left(\dfrac23\sqrt7\right)^2+4\left(\dfrac12\sqrt{\dfrac{703}3}\right)^2}=\sqrt{269}\approx16.40[/tex]
Scientists use models to represent physical situations that are difficult to explore
firsthand.
True
False
Answer:
I believe it is True
Explanation:
Which describes a difference between solar wind and a geomagnetic storm? Select the three correct answers. (2 points)
Solar wind sometimes results in geomagnetic storms, geomagnetic storms do not cause solar wind.
Geomagnetic storms travel at the speed of light, while solar wind takes four days to reach Earth.
Geomagnetic storms occur only occasionally, solar wind is constant.
Geomagnetic storms are associated with CMEs, solar wind is associated with the constant activity in the sun
Geomagnetic storms are constant, solar wind occurs only occasionally.
We have that the three correct answers are
"Solar wind sometimes results in geomagnetic storms, geomagnetic storms do not cause solar wind" is a correct statement from the definition above."Geomagnetic storms occur only occasionally, solar wind is constant."This statement is correct as the sun emission of solar wind particles are constant but Geomagnetic storms are occasional."Geomagnetic storms are associated with CMEs, solar wind is associated with the constant activity in the sun" This statement is correct as CMEs( Coronal Mass Ejections) are sometimes the main reason for Geomagnetic stormsWe First define the two Phenomenons
Solar Winds
These are Particles such as Plasma and other Harmful particles Dispersed by the sun of the a galaxy that can be harmful to Humans.
Geomagnetic storm
A Geometric storm is a kind of storm that comes about because of the an attack of the solar wind on earths magnetic field above atmosphere.
Therefore
"Solar wind sometimes results in geomagnetic storms, geomagnetic storms do not cause solar wind" is a correct statement from the definition above."Geomagnetic storms travel at the speed of light, while solar wind takes four days to reach Earth." This is false as Geometric storms are the Phenomenons that emanate on earth."Geomagnetic storms occur only occasionally, solar wind is constant."This statement is correct as the sun emission of solar wind particles are constant but Geomagnetic storms are occasional."Geomagnetic storms are associated with CMEs, solar wind is associated with the constant activity in the sun" This statement is correct as CMEs( Coronal Mass Ejections) are sometimes the main reason for Geomagnetic storms"Geomagnetic storms are constant, solar wind occurs only occasionally."This statement is False as Stated in the definitions above
In conclusion
The three correct answers are
"Solar wind sometimes results in geomagnetic storms, geomagnetic storms do not cause solar wind" is a correct statement from the definition above."Geomagnetic storms occur only occasionally, solar wind is constant."This statement is correct as the sun emission of solar wind particles are constant but Geomagnetic storms are occasional."Geomagnetic storms are associated with CMEs, solar wind is associated with the constant activity in the sun" This statement is correct as CMEs( Coronal Mass Ejections) are sometimes the main reason for Geomagnetic stormsFor more information on this visit
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What topic name in physics does this equation belong to? g = Fg/m
Extra Practice In Exercises 1-4, use the diagram. 1. Give two other names for CD.
Answer: I think it’s point cd and line cd
Explanation:
who is george washington? what does he do for america?
George Washington was an American political leader, military general, statesman and Founding Father of the United States, who serves as the first president of the United States from 1789 to 1797.
During the American Revolution, the led the colonial forces to victory over the British and became a national hero. In 1787, he was elected president of the convention that wrote the U.D. constitution. Two years later, Washington became the America's first president.
Question 4 A car of mass 820 kg has a maximum power of 30 kW and moves against a constant resistance of motion to 910 N. Calculate the maximum speed of the car in the following situation; b)Up an incline (hill) of 8.75° to the horizontal?
Answer:
P = W / t = m g s / t = m g v where work by auto = m g s
30 kw = 30000 watts = 30000 J / s
Work wasted = F v as shown above relating work and power
Work done against incline = m g s sin 8.75 and power against incline
= m g v sin 8.75 = 1222 v Joules / sec
power in moving auto = power available - power lost to friction
power in moving auto = 30000 - resistance = 30000 - 910 v
1222 v = 30000 - 910 v
v = 30000 / 2132 = 14 m/s
Note: constant resistance to motion must mean P = W / t = F s / t = F v
Maximum speed will be v = 14.07 m/s
What is power ?Power is defined time rate of doing work or delivering energy.
Work done = Force * displacement
Power = work done / time
= (Force * displacement ) / time
since , displacement / time = velocity
Power = force * (displacement / time ) = force * velocity
Power = mass * acceleration * velocity ( as force = mass * acceleration)
since , car is travelling up in an incline of 8.75° to the horizontal
hence , it will have two components of velocity
vertical component = v sin (theta ) = v sin(8.75°)
horizontal component = v cos (theta)= v cos (8.75°)
Power = m* a * v sin (theta )
= 820 * 9.8 * v *sin (8.75°) ( a = g = 9.8 m[tex]/s^{2}[/tex])
= 1221.472 v
Power lost due to resistance in motion = 910 * velocity = 910 v
Power = Total power - power lost due to resistance in motion
= 30 * [tex]10^{3}[/tex] - 910 v
30 * [tex]10^{3}[/tex] - 910 v = 1221.472 v
v = 14.07 m/s
Maximum speed will be v = 14.07 m/s
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Which type of bond and how many bonds would occur as carbon dioxide (CO2) is formed from carbon in Group IVA and oxygen in Group VIA?
A. Three metallic bonds
B. two ionic bonds
C. One covalent bond
D. Four covalent bonds
Answer:
The answer is D. Four covalent bounds
why is it important for heat sinks to be made of metal and have a large surface area?
fill the blank spaces with suitable terms a heat energy from bottom
to the top of atake is
1. An MR-2 starts from rest and accelerates westward to a speed of 27 m/s in
11.8 seconds.
a) What is its acceleration?
b) What is the displacement it covered?
Answer:
a) 2.28 m/s²
b) 159.86 m
Explanation:
Part A:
u = 0 m/s
v = 27 m/s
t = 11.8 seconds
a = ?
Formula:
v = u + at
=> 27 = 0 + a(11.8)
=> 27 = a(11.8)
=> a(11.8) = 27
=> a = 27/11.8
=> a = 2.28 m/s²
Part B:
s = ?
Formula:
s = (v² - u²)/2a
s = (27² - 0²) /2(2.28)
= 729/4.56
= 159.86 m
An acetate rods rubs against a cloth. What type of charge will the rod end up with?
A. Positive
B. Negative
C. Not enough info
D. Neutral
Answer:
I believe it's A
Explanation:
........
What is the field outside the capacitor plates in a parallel capacitor?
Answer is zero
Plz mark me brainlist
Explanation:
Outside two infinite parallel plates with opposite charge the electric field is zero, and that can be proved with Gauss's law using any possible Gaussian surface imaginable
Which of the following phrases best describes the term scientific model?
A. The application of scientific knowledge to make predictions about
an object, system, or process
B. An experiment in which variables are controlled
C. A physical copy of a scientific object, system, or process
D. A simplified representation used to explain or make predictions
about something
SUBMIT
Why is evolution called a scientific theory?
Answer:
Explanation:
Evolution is both a fact and a theory. Evolution is widely observable in laboratory and natural populations as they change over time. The fact that we need annual flu vaccines is one example of observable evolution. At the same time, evolutionary theory explains more than observations, as the succession on the fossil record. Hence, evolution is also the scientific theory that embodies biology, including all organisms and their characteristics. In this paper, we emphasize why evolution is the most important theory in biology. Evolution explains every biological detail, similar to how history explains many aspects of a current political situation. Only evolution explains the patterns observed in the fossil record. Examples include the succession in the fossil record; we cannot find the easily fossilized mammals before 300 million years ago; after the extinction of the dinosaurs, the fossil record indicates that mammals and birds radiated throughout the planet. Additionally, the fact that we are able to construct fairly consistent phylogenetic trees using distinct genetic markers in the genome is only explained by evolutionary theory. Finally, we show that the processes that drive evolution, both on short and long time scales, are observable facts.
The evolutionary theory is a scientific theory because its assumptions are well sustained by scientific data.
Scientific data refers to the body of knowledge obtained by using the scientific method.A scientific theory is a well-sustained explanation of one or more questions of the natural world, which was repeatedly tested and verified by using the scientific method.The theory of evolution by natural selection is a theory because it has been repeatedly corroborated through the scientific method.In conclusion, the evolutionary theory is a scientific theory because its assumptions are well sustained by scientific data.
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What is scintillator
Answer:
Scintillators are materials that transform high-energy radiation like X-rays or gamma-rays into visible light or near-visible light. They're commonly utilized in medical diagnostics, high-energy physics, and geophysical exploration as detectors.
Explanation:
i hope this helps
Pls help me 10 points
Answer:
d is the right answer
it's was helpful to you
The circled one please
Mark brainliest!!
Answer:
50µs
Explanation:
The conversion is that 1 second equals 1,000,000 micro seconds. Since we have 0.00005 seconds, we will multiply that to a million.
0.00005 * 1,000,000 = 50µs
Keep in mind that 50 only has 1 significant figure because any trailing zeroes before the decimal point do NOT count.
Best of Luck!
0.00005 seconds = 50 μs
Thank you
g A high-energy photon turns into and electron and a positron. (A positron has exactly the same mass as the electron, but opposite charge.) What is the longest wavelength that the photon can have for this process to occur
Answer:
2 m = E / c^2 where m is mass of electron
E = h v where v is the frequency ( nu) of the incident photon
E = h c / y where y is the incident wavelength (lambda)
2 m = h / (c y)
y = h / (2 m c) wavelength required
y = 6.62 * 10E-34 / (2 * 9.1 * 10E-31 * 3 * 10E8) m
y = 3.31 / 27.3 E-11 m
y = 1.21 E -12 m = .0121 Angstrom units
John took 0.75 hours to bicycle to his grandmother's house, a distance of 4 km. What is his velocity?
What are you solving for?
What’s the equation?
Show work!
Help pleaseee!
Answer:
5.3Km/hr
Explanation:
Velocity=Displacement/Time
D=4km;T=0.75hr
V=4/0.75=5.33..
John traveled at a speed of 5.3 km/h to get to his grandmother's house.
How is the rate of position change in relation to time measured?While velocity is the rate of change of an object's position with respect to time in a specific direction, speed is the rate of change of an object's position with respect to time overall. The speed of an item moving in a certain direction is referred to as its velocity. When there is a change in speed, direction, or both, the velocity also changes.
Given:
Time taken to travel, t = 0.75 h
Total distance travelled = 4 km
Let's imagine that John traveled to his grandmother's house in a single direction at a constant pace.
Velocity = Distance travelled in a given direction/Time
So, Velocity = 4 km/0.75 h = 5.3 ≈ 5km/h
John's speed in getting to his grandmother's residence was thus 5 km/h.
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A mass of 20kg which moved vertically produced a momentum of 300kg.m/s, how much power was needed to move the mass?
Answer:
Power is 3000 W
Explanation:
Momentum = mass × velocity
[tex]300 = 20 \times v \\ velocity = 15 \: {ms}^{ - 1} [/tex]
For power:
[tex]P = \frac{force \times distance}{time} \\ \\ P = force \times ( \frac{distance}{time} )[/tex]
but distance/time is velocity, so:
[tex]P = force \times velocity[/tex]
but force = mass × acceleration:
[tex]P = (mass \times acceleration) \times velocity \\ P = (20 \times 10) \times 15 \\ P = 3000 \: \: watts[/tex]
[ taken acceleration to be 10 m/s² ]
Elastic and inelastic collisions
Explanation:
A perfectly elastic collision is defined as one in which there is no loss of kinetic energy in the collision. An inelastic collision is one in which part of the kinetic energy is changed to some other form of energy in the collision.
A block lying on an inclined plane has a weight of 50 N. It just begins to slide down when the inclination of plane with the horizontal is 30°. The value of u is
Answer:
μ = tanθ = tan30 = 0.58
Explanation:
μ = force parallel/force perpendicular = mgsinθ/mgcosθ = tanθ
When astronauts get on a rocket and go outside Earth they float because gravity is affected by this
Answer:
Distance
Explanation:
Gravity is indirectly related to distance. This means if distance increases, gravitational pull decreases.
vận tốc là 12km|h tgian 2h hỏi quãng đường
A mass of 10kg is suspended from the end of a steel rod of length 2m and radius 1mm. What is the elongation of the rod beyond it's original length (Take E=200*10⁹Nm²)
Answer:
don't know what class are you which subject is this
