In the early 20th century, the average luminosity in Cepheid variable stars was related to: the period of time it takes to vary.
What is a cosmic distance?A cosmic distance can be defined as an accurate and precise measurement of the distance to celestial or astronomical objects such as:
GalaxiesStarsMoonSunIn the early 20th century, a discoery of the average luminosity in Cepheid variable stars was related by astronomers to the period of time it takes to vary and this helped tremendously in the measurement of cosmic distances.
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Choose all the answers that apply.
Earth:
takes longer than 365 days to orbit the sun
has the most circular orbit in the solar system
has the largest satellite relative to its planet
has seasons because of a tilted axis
is a perfect sphere
Answer:
takes longer than 365 days to orbit the sun
has seasons because of a tilted axis
Note: We see 365 days for a year - from an external point of view, a year would take 366 days to orbit the sun - this is because it takes slightly less than 24 hours from sunrise to sunrise because of the rotation of the earth about the sun (a sidereal year is 366 days as compared to 365 days observed on earth)
Water is streaming downward from a faucet opening with an area of 3.0 x 10-5 m2. It leaves the faucet with a speed of 5.0 m/s. The cross sectional area of the stream 0.50 m below the faucet is:
The cross sectional area of the stream 0.50 m below the faucet is 2.54 x 10⁻⁵ m².
Speed of the water 0.5 m below the faucetThe speed of the water at the lower level is determined using Bernoulli's equation as follows;
P₀ + ρgΔh + ¹/₂ρv₁² = P₀ + 0 + ¹/₂ρv₂²
ρgΔh + ¹/₂ρv₁² = ¹/₂ρv₂²
gΔh + ¹/₂v₁² = ¹/₂v₂²
9.8(0.5) + ¹/₂(5)² = ¹/₂v₂²
2(17.4) = v₂²
34.8 = v₂²
v₂ = √34.8
v₂ = 5.9 m/s
Continuity equationA₁v₁ = A₂v₂
A₂ = A₁v₁ /v₂
A₂ = (3.0 x 10⁻⁵ x 5) / (5.9)
A₂ = 2.54 x 10⁻⁵ m²
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Explain how sound waves are created and how they travel
Answer:
Sound is produced when an object vibrates, creating a pressure wave. This pressure wave causes particles in the surrounding medium (air, water, or solid) to have vibrational motion. As the particles vibrate, they move nearby particles, transmitting the sound further through the medium.
Explanation:
Light of different colors is emitted from different stars because :.
Answer:
Different temperatures
Explanation:
A sailor pulls a boat along a dock using a rope at an angle of 35. 0º with the horizontal. How much work does the sailor do if he exerts a force of 455 N on the rope and pulls the boat 9. 50 m?
Calculate the kinetic energy of a truck that has a mass of 1900 kg and is moving at 45 m/s.
Find the mass of a car that is traveling at a velocity of 75 m/s North. The car has 5,040,000 J of kinetic energy.
How fast is a ball rolling if it contains 108 J of kinetic energy and has a mass of 3. 5 kg?
At an accident science on a level road, investigators measure a car’s skid mark to be 85 m long. The accident occurred on a rainy day, the coefficient of friction was estimated to be 0. 25. What was the speed of the car when the driver slammed on and locked the brakes?
A new conveyor system at the local packaging plan will utilize a motor-powered mechanical arm to exert an average force of 980 N to push large crates a distance of 15 meters in 30 seconds. Determine the power output required of such a motor.
Josh and Jake are both helping to build a brick wall which is 6 meters in height. They each lay 350 bricks, but Josh finishes this task in 2 hours while Jake requires 5. 5 hours to complete his part. Who does more work, or do they both do the same amount? Who has more power? Explain.
please help me
Answer:
What work is done when a person pushes an 80 kg washing machine 12m across the floor. The force of friction between the washing machine and floor is 500 N.
A sailor pulls a boat along a dock using a rope at an angle of 60° with the horizontal. How much work does the sailor do if he exerts a force of 255 N on the rope and pulls the boat 4.0m?
Explanation:
How does the amount of solar energy change as Earth orbits the sun
Explanation:
As the Earth orbits the Sun, the tilt causes one hemisphere and then the other to receive more direct sunlight and to have longer days. The total energy received each day at the top of the atmosphere depends on latitude
Answer:
She is right!
Have a good day/Night!
Explanation:
Rex
A small bar magnet pulls on a larger one with a force of 79 Newtons.
What is the magnitude of the force the larger one exerts on the smaller one?
Answer in units of N.
Answer:
79 N ( the same)
Explanation:
(02.06 LC)
Etiquette determines which (5 points)
Answer:
Etiquette determines which behaviors are polite and impolite among players and team. It is a code of polite conduct according to social norms and efficiency. Etiquette as a societal rule is formed to enhance positive human relation when interacting and can reduce conflicts in the society. A person who is aware of the etiquette in a given situation will be more confident, comfortable and competent thus making even those around him or her at ease.
343. W/M^2 of energy is emitted by the sun to the earth. How much actually reaches the earth's surface?
A. About one fourth
B. Almost all
C. About a third
D. About half
If 343 W/m² of energy is emitted by the sun to the earth, the quantity that reaches the earth is : ( D ) which is about half.
What is radiation?Radiation is the energy exchange that does not require a material medium for propagation.This is the process in which the sun exchanges heat with the earth.
Analysis:
When heat is exchanged between two bodies, heat is either, absorbed, transmitted or reflected. In the the cloud, energy is reflected back to the sun since the clouds are translucent, it allows a part to reach the clouds.
In conclusion, About half of this energy gets to the earth.
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Answer:
The correct answer is A. About one fourth.planation:
*PIC PROVIDED*
A solid disk of mass (M) and radius (R) rolls without slipping with a linear speed of (v). Find the maximum vertical height (h) to which it can roll if it goes up an incline. Answer in terms of M, R, v, and g.
(I assume g is for gravity)
Answer:
1/2 M V^2 = M g H
Initial kinetic energy equals final potential energy
H = V^2 / (2 g) satisfies given conditions
Which pair of triangles can be proven congruent by the hl theorem?
The pairs of triangles that can be proven congruent by the hl theorem is the right angled triangle.
What is mearnt be the HL theorm?The HL theorem is also known as the Hypothenus Leg theorem, it states that "the hypotenuse and leg of one right triangle are congruent to the hypotenuse and leg of another right triangle, then the two triangles are congruent."
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Answer:
B
Explanation:
Hello people ~
Which of the following options are correct?
If a conductor has a potential V 4- 0 and there are no charges anywhere else outside, then _____
(a) there must not be charges on the surface or inside itself.
(b) there cannot be any charge in the body of the conductor.
(c) there must be charges only on the surface.
(d) there must be charges inside the surface.
The charge would be in equilibrium so there would be no charge in the body of the conductor.
Answer:
(b) there cannot be any charge in the body of the conductor
Answer:
B
Explanation:
Note the line that there is no charges anywhere else outside means the charge is placed in equilibrium position.
Hence there cannot be any charge in the body of conductor
A 1.10-kg block of wood sits at the edge of a table, 0.790 m above the floor. A 1.15×10−2-kg bullet moving horizontally with a speed of 700 m/s embeds itself within the block.
What horizontal distance does the block cover before hitting the ground?
Answer:
I think u missspelled something be cause the the sum would be a good 0.2927
2. It is to bring down the foot forcibly to the f a heavy step) with or without weight. 2 Ormain lateral position - This is done at sho
Noah plans on using a pendulum to determine the height of a tower. He attaches a mass to the end of a thin cord hanging from the tower's ceiling (let's assume the cord almost touches the ground). Noah determines the period of oscillation to be 12 s. How high is the tower?
The height of the tower is 35.75 m.
What is height?Height is the vertical distance between two points.
To calculate the height of the tower, we use the formula below.
Formula:
T = 2π√(L/g)............ Equation 1Where:
T = Period of oscillationπ = PieL = height of the towerg = acceleration due to gravity.From the question,
Given:
T = 12 sg = 9.8 m/s²π = 3.14Substitiute these values into equation 1 and solve for L
12 = 2(3.14)√(L/9.8)12 = 6.28√(L/9.8)√(L/9.8) = 12/6.28√(L/9.8) = 1.91L/9.8 = (1.91)²L/9.8 = 3.6481L = 9.8×3.6481L = 35.75 mHence, the height of the tower is 35.75 m.
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A new rechargeable battery pack is available for products that use aa batteries. Which of the following best explains how the data files in the table can be used to send a targeted e-mail to only those customers who have purchased products that use aa batteries to let them know about the new accessory?.
Answer:
D
Explanation:
Use the products file to generate a list of product IDs that use AA batteries, then use the list of product IDs to search the purchases file to generate a list of customer IDs, then use the list of customer IDs to search the customers file to generate a list of e-mail addresses
1. Potential energy and a roller coaster. A 1000-kg roller coaster car moves from point A to B then C.
(a) What is the potential energy at B and C
relative to A?
(b) What is the change in potential energy
as it goes from B to C?
(c) What is the potential energy at B and C relative to point C?
(d) What is the change in potential energy as it goes from B to C?
Answer:(a) With our choice for the zero level for potential energy of the car-Earth system when the car is at point B ,
U
B
=0
When the car is at point A, the potential energy of the car-Earth system is given by
U
A
=mgy
where y is the vertical height above zero level. With 135ft=41.1m, this height is found as:
y=(41.1m)sin40.0
0
=26.4m
Thus,
U
A
=(1000kg)(9.80m/s
2
)(26.4m)=2.59∗10
5
J
The change in potential energy of the car-Earth system as the car moves from A to B is
U
B
−U
A
=0−2.59∗10
5
J=−2.59∗10
5
J
(b) With our choice of the zero configuration for the potential energy of the car-Earth system when the car is at point A, we have U
A
=0. The potential energy of the system when the car is at point B is given by U
B
=mgy, where y is the vertical distance of point B below point A. In part (a), we found the magnitude of this distance to be 26.5m. Because this distance is now below the zero reference level, it is a negative number.
Thus,
Hello people ~
Two copper spheres of the same radius, one solid and the other hollow, are charged to the same potential. Which will have more charge?
(a) Solid sphere
(b) Hollow sphere
(c) Both will have an equal charge
(d) None of these
C
Let's see how
We know the rule
[tex]\\ \rm\rightarrowtail V=\dfrac{Kq}{r}[/tex]
[tex]\\ \rm\rightarrowtail Kq=vr[/tex]
[tex]\\ \rm\rightarrowtail q\propto r[/tex]
As radius is same charge will be same in both
Hence they both have same charge
A body travels a distance of 20m in the 7th second and 24m in the 9th second. How much distance shall it travel in the 15th second?
Answer:
36 m
Explanation:
We can consider this to be an AP.
Then,
a₇ = 20a₉ = 24Subtract a₇ from a₉.
a + 8d - a + 6d = 24 - 202d = 4d = 2a + 6(2) = 20a = 8Finding a₁₅
a₁₅ = a + 14da₁₅ = 8 + 14(2)a₁₅ = 8 + 28a₁₅ = 36 mFind rate of change
f(9)-f(7)/9-724-20/9-74/22m/sSo
Distance travel in 6 s
Speed×Time6(2)12mDistance in 15s:-
12+2436mIn this lab, you will need to be able to describe how multiple waves interact with each other. 1) This does not add too much mathematical complexity to the wave equation (Eq. 2), and 2) it allows us to develop a closer approximation of real-life situations as well (e. G. Interacting ripple patterns in a pond, music, atomic physics, etc. ). Here, you will explore the superposition of two waves, y1 and y2, where:
The superposition of waves due to their interaction can either produce a constructive or destructive interference.
What is wave superposition?Wave superposition refers to the the interaction of two or more waves when their parts overlap.
Example of wave superposition is multiple waves travelling through a rope.
The superposition principle states that when two or more waves overlap in space, the resultant disturbance is equal to the algebraic sum of the individual disturbances.
Based on phase difference between two or more waves, the superposition if the waves can result in either constructive or destructive interference .
Therefore, the superposition of waves due to their interaction can either produce a constructive or destructive interference.
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A +1.4 nC charge exerts a repulsive force of 20.0 mN on a second charge
which is located a distance of 2.2 m away from it. What is the magnitude
and sign of the second charge?
Answer:
+ .00769 C
Explanation:
Whoever 'katie' is , removed my previous, innocuous answer for some reason....
The force is repulsive , so the charge is also POSITIVE
f = k q1 q2 / r^2
k = Coulombs constant = 8.98755 x 10^9 kg m^3 . (s^2 C^2)
q 1 = 1.4 x 10^-9 C f = 20 x 10^-3 N
r = 2.2 m q2 = ?
Sub in the values to get q 2 = + .00769 C
A 1,508 kg car rolling on a horizontal surface has a speed of 20.8 km/hr when it strikes a horizontal coiled spring and is brought to rest in a distance of 6.87 m. What is the spring constant (in N/m) of the spring
Answer:
Approximately [tex]1.79 \times 10^{5}\; {\rm N \cdot m^{-1}}[/tex], assuming friction between the vehicle and the ground is negligible.
Explanation:
Let [tex]m[/tex] denote the mass of the vehicle. Let [tex]v[/tex] denote the initial velocity of the vehicle. Let [tex]k[/tex] denote the spring constant (needs to be found.) Let [tex]x[/tex] denote the maximum displacement of the spring.
Convert velocity of the vehicle to standard units (meters per second):
[tex]\begin{aligned}v &= 20.8\; {\rm km \cdot h^{-1}} \times \frac{1000\; {\rm m}}{1\; {\rm km}} \times \frac{1\; {\rm h}}{3600\; {\rm s}} \\ &\approx 1.908\; {\rm m \cdot s^{-1}}\end{aligned}[/tex].
Initial kinetic energy ([tex]{\rm KE}[/tex]) of the vehicle:
[tex]\begin{aligned}\frac{1}{2}\, m \, v^{2}\end{aligned}[/tex].
When the vehicle is brought to a rest, the elastic potential energy ([tex]\text{EPE}[/tex]) stored in the spring would be:
[tex]\displaystyle \frac{1}{2}\, k\, x^{2}[/tex].
By the conservation of energy, if the friction between the vehicle and the ground is negligible, the initial [tex]\text{KE}[/tex] of the vehicle should be equal to the [tex]{\rm EPE}[/tex] of the vehicle. In other words:
[tex]\begin{aligned}\frac{1}{2}\, m \, v^{2} &= \frac{1}{2}\, k\, x^{2}\end{aligned}[/tex].
Rearrange this equation to find an expression for [tex]k[/tex], the spring constant:
[tex]\begin{aligned}k &= \frac{m\, v }{x^{2}}\end{aligned}[/tex].
Substitute in the given values [tex]m = 1508\; {\rm kg}[/tex], [tex]v \approx 1.908\; {\rm m\cdot s^{-1}}[/tex], and [tex]x = 6.87\; {\rm m}[/tex]:
[tex]\begin{aligned}k &= \frac{m\, v }{x^{2}} \\ &\approx \frac{1508\; {\rm kg} \times 1.908\; {\rm m\cdot s^{-1}}}{(6.87\; {\rm m})^{2}} \\ &\approx 1.79 \times 10^{5}\; {\rm kg \cdot m \cdot s^{-2} \cdot m^{-3}}\\ &\approx 1.79 \times 10^{5}\; {\rm N \cdot m^{-1}}\end{aligned}[/tex]
Objects 1 and 2
attract each other with
a electrostatic force
of 72.0 units. If the charge of Object
is one-third the
original value AND the charge of object 2 is doubled AND
the distance separating Objects 1 and 2 is doubled, then the
new electrostatic force will be
units.
Answer:
12 units
Explanation:
Original F = C q1q2/r^2 now change the parameters
New F = C 1/3 q1 2 q2 / (2r)^2
= 2/12 C q1q2/r^2 <=======the new force is 1/6 of original
1/6 * 72 = 12 units
During which two moon phases would the amount of light reflected from the moon appear to be equal from Earth? Why does this occur at different times in a month? (AKS6a, DOK 3)
A.
The light reflected appears the same during the new moon and full moon phases because the sun, moon and Earth are aligned.
B.
The light reflected appears the same during the new moon and first quarter moon phases because the sun, moon and Earth are at the same angles.
C.
The light reflected appears the same during the full moon and third quarter moon phases because the sun, moon and Earth are at the same angles.
D.
The light reflected during the first quarter and third quarter moon phases appears equal because the sun, moon and Earth are at right angles.
The moon phase shows that D. light reflected during the first quarter and third quarter moon phases appears equal because the sun, moon and Earth are at right angles.
What is a moon phase?It should be noted that the moon phase simply means the portion of the moon that we can see from the Earth.
In this case, the light reflected during the first quarter and third quarter moon phases appears equal because the sun, moon and Earth are at right angles.
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As velocity____kinetic energy _____ and potential energy _____
Answer:
increases increases decreases
Explanation:
For an object falling from a height
A planet's moon travels in an approximately circular orbit of radius 8.6 107 m with a period of 6 h 25 min. Calculate the mass of the planet from this information.
Answer:
m v^2 / R = G M m / R^2 gravitational attraction = centripetal force
M = v^2 R / G solving for M
period = 6 h 25 min = (6 * 3600 + 25 * 60) sec = 23,100 sec = T
v = 2 pi R / T
M = 4 pi^2 R^3 / (G T^2)
M = 39.5 * (8.6E7)^3 / (6.67E-11 * 2.31E4^2)
M = 39.5 * 636 / (6.67 * 5.34) * 10^24
M = 7.05 * 10^26 kg
A planet has a mass 0.051 times the mass of Earth and a diameter of about 0.160 times the diameter of Earth. What is the acceleration of a body falling near the surface of this planet
Answer:
Gravity on planet is 2 times earth gravity
Explanation:
Grav force = G m1 m2 / (r^2) now change m1 and r
= G .051m1 m2 / ( .16 r)^2
= .051 /.0256 G m1 m2 / r^2
.051 /.0256 = ~ 2
A corona is a circle of light that can be seen around the Moon during a solar eclipse.
O True
False
An ideal gas, initially at a volume of 0.777778 L and pressure of 9 kPa, undergoes isothermal expansion until its volume is 7 L and its pressure is 1 kPa. Calculate the work done by the gas during this process. Answer in units of J.
For an ideal gas, initially at a volume of 0.777778 L, the work done by the gas during this process is mathematically given as
w=15.380613
What is the work done by the gas during this process.?Generally, the equation for the work done is mathematically given as
W=p1v1invfvi
Therefore
v2=p1v1/p2
v2=9*1.0.77778/1
v2=7.00002
In conclusion
w=7.00002ln7/0.777778
w=15.380613
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How does fission differ from fusion?
Explanation:
Fission is the splitting of a heavy, unstable nucleus into two lighter nuclei, and fusion is the process where two light nuclei combine together releasing vast amounts of energy.