The term 'Zero Age Main Sequence' refers to the time when a new star stops contracting and hydrogen fusion starts.A. TrueB. False
Answer:
True
Explanation:
When a star has reached the main sequence stage, hydrogen is converted into helium by nuclear fusion, . Also, the gravity and pressure are balanced because the star does not radiate more heat than it generates. A star usually spends most of its lifetime at this stage.
The Zero Age Main Sequence is the period during the main sequence when a star stops contracting, and begin to fuse hydrogen in its core.
A 50 kg child is riding on a carousel (merry-go-round) at a constant speed of 5 m/s. What is the magnitude of the change in the child's momentum ∣Δp⃗ ∣∣ in going all the way around (360∘)?In going halfway around (180∘)? It is very helpful to draw a diagram, and to do the vector subtraction graphically.
Answer:
a) [tex]\mathbf{|\Delta p^{\to}_{11}| = 0 \ kg.m/s}[/tex]
b) [tex]\mathbf{|\Delta p^{\to}_{12}| = 500 \ kg.m/s}[/tex]
Explanation:
From the image attached below.
Suppose the child goes all the way around, i.e., 360, the child will execute a movement of 1 complete revolution and be at his starting point. At that point, the velocity vector is towards the y-direction.
Thus, the velocity of the child is:
[tex]v_1^{\to} = v \hat _v_1} \\ \\ v_1^{\to} = (5)(0,1,0)\\ \\ v_1^{\to} = (0,5,0) \ m/s[/tex]
the momentum will be:
[tex]p_1^{\to} = m v_1^{\to} \\ \\ p_1^{\to} = (50)(0,5,0) \\ \\ p_1^{\to} = (0,250,0) \ kg.m/s[/tex]
the change in momentum now is [tex]\Delta p = p_1^{\to} -p_1^{\to}[/tex] since that is the child's momentum initially.
∴ [tex]\Delta p =(0,250,0) - (0,250,0)[/tex]
[tex]\mathbf{\Delta p =(0,0,0) \ kg.m/s}[/tex]
By subtracting the two vector graphically as being asked in the question, we have :
[tex]|\Delta p^{\to}_{11}| = \sqrt{(0)^2+(0)^2 +(0)^2 }[/tex]
[tex]\mathbf{|\Delta p^{\to}_{11}| = 0 \ kg.m/s}[/tex]
b) In going halfway around (180°), the child will be opposite with respect to the starting point. Hence, the velocity vector will be in the negative y-direction.
Thus, the velocity of the child is:
[tex]v_2^{\to} = v \hat _v_2} \\ \\ v_2^{\to} = (5)(0,-1,0)\\ \\ v_2^{\to} = (0,-5,0) \ m/s[/tex]
the momentum will be:
[tex]p_2^{\to} = m v_2^{\to} \\ \\ p_2^{\to} = (50)(0,-5,0) \\ \\ p_2^{\to} = (0,-250,0) \ kg.m/s[/tex]
the change in momentum now is [tex]\Delta p = p_2^{\to} -p_1^{\to}[/tex] since that is the child's momentum initially.
∴ [tex]\Delta p =(0,-250,0) - (0,250,0)[/tex]
[tex]{\Delta p =(0,-500,0) \ kg.m/s[/tex]
By subtracting the two vector graphically as being asked in the question, we have :
[tex]|\Delta p^{\to}_{12}| = \sqrt{(0)^2+(-500)^2 +(0)^2 }[/tex]
[tex]|\Delta p^{\to}_{12}| = \sqrt{250000}[/tex]
[tex]\mathbf{|\Delta p^{\to}_{12}| = 500 \ kg.m/s}[/tex]
15. Two like charges: A. Attract each other B. Repel each other C. Must be neutrons D. Neutralize each other
Answer:
B. Repel each other
Explanation:
Two like charges have the same sign. Example an electron with a negative charge (-e) and another electron with same charge(-e). Or a proton with a positive charge (+e) and another proton with same charge (+e). Since each of these pair charges have the same sign, they will repel each other.
On the other hand, if the charges are opposite, ie negative charge and positive charge, they will attract each other.
B. Repel each other
Industrial espionage is the use of spying techniques to find out key information that is of economic value.
a) true
b) false
Answer:
The given statement is "True".
Explanation:
Industrial spying or espionage seems to be the surreptitious but sometimes unconstitutional method of trying to investigate competition in the market to gain a competitive advantage throughout the commercial enterprise. The investigation's goal may be a closely guarded secret including a patented product design or formulation, or growth strategy details.an Alpha particle moving in north direction give reasons
Your question has been heard loud and clear.
An alpha particle , can move in any direction randomly. But with a magnetic field , we can deflect the alpha particle in any direction we want.
So , the magnetic field must be placed to the west of the alpha particle , so that the particle gets deflected and moves towards the north direction.
Thank you.
Like AL2006 said reasons for what
1. An insect inside a bus flies from the back toward the front at 2 m/s. The bus is moving in a
straight line at 20 m/s. What is the total speed of the insect as seen by a person standing
side of the road?
What is a true statement about models in science? A. Models change to accommodate new discoveries. B. Models are only used by scientists. C. Models never change. D. Models are only used by engineers.
Answer:
Models change to accommodate new discoveries
Explanation:
Owing to the dynamism of science, scientific models also change to accommodate new ideas and discoveries. Science is not a static body of knowledge. Research consistently brings new information to the fore. This propels a change in certain scientific models to accommodate the new discoveries and present a more accurate representation of phenomena in nature.
Hence, scientific models change to accommodate new discoveries.
Answer: Models change to accommodate new discoveries.
Explanation: I took the test
A jet makes a landing traveling due east with a speed of 115 m/s. If the jet comes to rest in 13.0 s, what is the magnitude of its average acceleration
Answer:
8.846 m/s²
Explanation:
From the question,
The magnitude of the average acceleration is given as,
a = (v-u)/t.................. Equation 1
Where a = acceleration of the jet, v = final velocity of the jet, u = initial velocity of the jet, t = time taken for the jet to come to rest.
Given: v = 115 m/s, u = 0 m/s( from rest), t = 13.0 s
Substitute these values into equation 1
a = (115-0)/13.0
a = 115/13
a = 8.846 m/s²
Hence the magnitude of the average acceleration of the jet is 8.846 m/s²
Answer:
The value is [tex]a = 8.85 \ m/s^2[/tex]
Explanation:
From the question we are told that
The speed is [tex]v = 115\ m/s[/tex]
The time taken is t = 13.0
The initial speed is [tex]u = 0 \ m/s[/tex]
Generally the magnitude of the average acceleration is mathematically represented as
[tex]a = \frac{v-u}{ t}[/tex]
=> [tex]a = \frac{ 115 -0}{ 13}[/tex]
=> [tex]a = 8.85 \ m/s^2[/tex]
Which of the following are subjects of scientific laws?a. gravityb. motionc. thermodynamics
1st block
Worksheet: Metric Prefixes
A. Circle the larger unit:
1.millimeter, centimeter
2. kilogram, megagram
3. microsecond, millisecond
4.dL, mL
5.mg, kg
Answer:
2
Explanation:
kilogram and megagram is the larger unit
What linear speed must an Earth satellite have to be in a circular orbit at an altitude of 203 km above Earth's surface
Answer:
7,790.38 m/s
Explanation:
Given the following :
What linear speed must an Earth satellite have to be in a circular orbit at an altitude of 203 km above Earth's surface
Altitude = 203 km
Using the formula :
V = √GM/r
Where G = gravitational constant =6.67×10^-11
Kindly check attached picture for detailed explanation.
What is the average power output (in W) of a heart defibrillator that dissipates 435 J of energy in 10.5 ms?
Answer:
The power is [tex]P = 41429 \ W[/tex]
Explanation:
From the question we are told that
The energy is [tex]E = 435 \ J[/tex]
The time taken is [tex]t = 10.5 \ ms = 10.5 *10^{-3} \ s[/tex]
Generally the the average power is mathematically represented as
[tex]P = \frac{E}{t}[/tex]
=> [tex]P = \frac{ 435}{ 10.5*10^{-3}}[/tex]
=> [tex]P = 41429 \ W[/tex]
what is force magnifier for class 6
Answer:
I think it will helps you dude!! :)
A person runs around a 400 m track. What is this person’s distance? What is this person’s displacement?
Explanation:
The distance is the length of the path, or 400 m.
The displacement is the difference between the final position and the initial position. Since the track is a circle and the end back where they started, the displacement is 0 m.
If a person runs around a 400 m track,then the distance covered by the person would be 400 meters, while the displacement covered by the person would be zero meters.
What is displacement?An object's position changes if it moves in relation to a reference frame, such as when a passenger moves to the back of an airplane or a professor moves to the right in relation to a whiteboard.
Displacement describes this shift in location.
As given in the problem If a person runs around a 400 m track, then we have to find the distance and the displacement covered by him,
The distance is 400 meters, which is how long the path is.
The distance between the end location and the starting position is known as displacement. The displacement is 0 m since the track is round and ends where it began.
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while working out a man performed 375J of work in 11 seconds what was his power
Answer:
power=work done /time taken
therefore..375/11
=34.09
there he used 34.1
Which observation is the most objective? a My frog died after 3 days in the aquarium. I will miss him. b My frog died after three days in the aquarium. We will test the temperature and water conditions to find out why. c Frogs tend to die in captivity. Ours did after three days.
Answer:
b
Explanation:
a looks so silly
Calculate the kinetic energy, in joules of a 1160-kg automobile moving at 19.0 m/s.
Answer:
Explanation:
K.E=1/2 mv²
m=1160 kg
v=19.0 m/s
so k.e=1/2*1160*(19.0)²
K.E=1/2*1160*361
K.E=1/2*418760
K.E=209380=2.0*10^5 j
A lens that is "optically perfect" is still limited by diffraction effects. Suppose a lens has a diameter of 150 mm and a focal length of 620 mm. A. Find the angular width (that is, the angle from the bottom to the top) of the central maximum in the diffraction pattern formed by this lens when illuminated with 520 nm light.B. What is the linear width (diameter) of the central maximum at the focal distance of the lens?
Answer:
a
w = 8.46 *10^{-6} \ rad
b
D =5.24 *10^{-6}
Explanation:
From the question we are told that
The diameter of the lens is [tex]d = 150 \ mm = 150*10^{-3} \ m[/tex]
The focal length is [tex]f = 620 mm = 620 *10^{-3} \ m[/tex]
The wavelength is [tex]\lambda = 520 \ nm = 520 *10^{-9} \ m[/tex]
Generally the angular width is mathematically represented as
[tex]w = 2 \theta[/tex]
Here [tex]\theta[/tex] is the angular radius of the central maxima which is mathematically represented as
[tex]\theta = \frac{1.22* \lambda }{ d}[/tex]
=> [tex]\theta = \frac{1.22 * 520 *10^{-9}}{ 150 *10^{-3}}[/tex]
=> [tex]4.23 *10^{-6} \ rad[/tex]
Hence
[tex]w = 2 * 4.23 *10^{-6}[/tex]
=> [tex]w = 8.46 *10^{-6} \ rad[/tex]
Generally linear diameter is mathematically represented as
[tex]D = 2 * R[/tex]
Where [tex]R[/tex] is the linear radius which is mathematically represented as
[tex]R = \frac{1.22 * f * \lambda }{ d}[/tex]
=> [tex]R= \frac{1.22 * 620 *10^{-3} * 520 *10^{-9}}{150 *10^{-3}}[/tex]
=> [tex]R = 2.62*10^{-6} \ m[/tex]
Thus
[tex]D = 2 * 2.62 *10^{-6}[/tex]
[tex]D =5.24 *10^{-6}[/tex]
Nina and Jon are practicing an ice skating routine. Nina is standing still. Jon, who is twice as heavy as Nina, skates toward her, pushing Nina away with force f. Assuming the system is closed, which statement is correct about this system? a. Nina experiences a force equal to f/2. b. Nina experiences a force equal to f^2. c. Nina experiences a force equal to 2f. d. Nina experiences a force equal to f.
Answer:
A
Explanation:
• Nina experiences a force equal to f.
Answer:
Nina experiences a force equal to f
Explanation:
got to get that 2nd answer slot correct too before an abusive expert verifier with an alt comes in and purposely verifies the wrong answer
A farmer lifts his hay bales into the top loft of his barn by walking his horse forward with a constant velocity of 8 ft/s. Determine the velocity and acceleration of the hay bale when the horse is 10 ft away from the barn.
Answer:
Velocity = 8 ft/s
Acceleration = 0 m/s²
Explanation:
Since, the horse is moving with a constant velocity, whose magnitude is given as equal to 8 ft/s. Therefore, it will have the same velocity when it is 10 ft away from the barn. And the velocity of hay bale will be same as the velocity of horse, as the horse is carrying the bales. Therefore:
Velocity = 8 ft/s
Coming to the second part of the question, which relates to the acceleration of the hay bale, when horse is 10 ft away from the barn. The formula for acceleration is given as:
Acceleration = Change in Velocity/ Time
But, the velocity of the horse in constant, which means there is no change in velocity. Hence,
Change in Velocity = 0
Therefore,
Acceleration = 0/Time
Acceleration 0 m/s²
What do civic heroes contribute to their society?
the quest for civic virtue
Explanation:
improving schools, the society....to help educators like yourself, the bill of rights institute has written a New classroom-friendly curriculum called Heroes and Villains....
Anyone able to also give me the working to how they figured it out?
Answer:
Lamp 1: 4 Volts, and 0.2 Amps
Lamp 2 : 4 Volts, and 0.2 Amps
Explanation:
Considering that the three lamps are equal (they have the same resistance R), we can find the actual resistance of the lamps with the information they provide that the potential difference measured across lamp 3 is 8 volts, using Ohm's Law:
[tex]V = I\,*\,R\\R = \frac{V}{I}\\R= \frac{8}{0.4} \\R = 20\,\,\Omega[/tex]
We can also estimate the potential difference across the lamps 1 and 2 (which are connected in parallel) using Kirchhoff's loop law, which tells us that the 12 volts provided by the battery should equal the addition of voltage drops in lamp 3 plus the drop in the parallel combination of lamps 1 and 2 (call that X):
12 V = 8 V + X
X = 12 - 8 = 4 V
Now, the current circulating through lamp 1 should be given by Ohm's Law:
[tex]V = I\,*\,R\\I = \frac{V}{R} \\I = \frac{4}{20}\\I = 0.2 \,\,Amps[/tex]
Notice that lamp 2 is equal to lamp 1 so the current value should be the same: 0.2 Amps
A large magnetic flux change through a coil must induce a greater emf in the coil than a small flux change. A) True B) False
Answer:
False
Explanation:
Faraday's law gives the relationship between the induced emf and the rate of change of magnetic flux i.e.
[tex]\epsilon=\dfrac{-d\phi}{dt}[/tex]
The given statement "A large magnetic flux change through a coil must induce a greater emf in the coil than a small flux change" is false. The reason is that if the rate of change of magnetic flux is greater, then its will induce more emf. It would mean it does not say about emf.
Hence, it is false.
Why do scientists need creativity? What is gravity? Why are two objects with mass drawn to each other? List the two things that affect gravitational force. How are mass and weight different? Why does weight change depending on location? Explain in your own words the law of universal gravitation. Why does gravitational force vary between objects? How do we know how much gravitational force objects have? How does distance affect gravity? answer them all
Answer:
The strength of the gravitational force between two objects depends on two factors, mass and distance. the force of gravity the masses exert on each other.
the gravitational force is directly proportional to the mass of both interacting objects, more massive objects will attract each other with a greater gravitational force.
mass and distance.
The difference between mass and weight is that mass is the amount of matter in a material, while weight is a measure of how the force of gravity acts upon that mass.
A person can weigh differently at various place on Earth because of the fluctuations in Earth's gravity.
We call the gravitational force attractive because it always tries to pull masses together, it never pushes them apart. In fact, every object, including you, is pulling on every other object in the entire universe!
Since the gravitational force is directly proportional to the mass of both interacting objects, more massive objects will attract each other with a greater gravitational force
Its weight is determined by the degree to which gravitational force acts on it.
the force of gravity the masses exert on each other. increases, the force of gravity decreases
The mass of the objects and their separation from one another determine the gravitational force's strength. The gravitational pull of masses on one another.
What affect gravitational force?Mass is a measure of the quantity of substance in a material, whereas weight measures how the force of gravity acts upon a mass.
Because of variations in Earth's gravity, a person's weight might vary depending on where they are on the planet.
The gravitational force is referred to as attractive because it continually tries to pull masses together rather than push them apart. In truth, you and everything else in the universe are being pulled in different directions.
Therefore, Greater gravitational forces will pull more massive objects toward one another because gravitational force is directly proportional to the mass of both interacting objects.
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The presence of dwarf galaxies around the Milky Way supports what picture of our galaxy’s formation?
Answer:
The presence of dwarf galaxies around the Milky Way supports what picture that our galaxy was formed by a coming together or combination of smaller systems
(a) A narrow beam of light containing yellow (580 nm) and green (550 nm) wavelengths goes from polystyrene to air, striking the surface at a 30.0°30.0° incident angle. What is the angle between the colors when they emerge?
Answer:
0.043°
Explanation:
Snell's law States that the ratio of the angle of incidence to angle of refraction is a constant for a given pair of media.
n = sin(i)/sin(r)
n1/n2 = sin(i)/sin(r)
For the green polystyrene
n2 = refractive index of green polystyrene = 1.493
n1 = refractive index of air = 1
1/1.493= sin30°/sin(r1)
sin(r1) = sin30°×1.493
sin(r1) = 0.5×1.493
sin(r1) = 0.7465
r1 = sin^-1(0.7465)
r1 = 48.288°
For the yellow polystyrene
n2 = refractive index of yellow polystyrene = 1.492
n1 = refractive index of air = 1
1.492/1= sin30°/sin(r2)
sin(r2) = sin30°×1.492
sin(r2) = 0.5×1.492
sin(r2) = 0.746
r2 = sin^-1(0.746)
r2 = 48.245°
The angle between the colors when they emerge = r1-r2
angle between the colors when they emerge = 48.288°-48.245°
angle between the colors when they emerge = 0.043°
You drop a ball from a height of 1.7 m, and it bounces back to a height of 1.2 m.
Part A) What fraction of its initial energy is lost during the bounce? Express your answer using two significant figures.
Part B) What is the ball's speed just before the bounce? Express your answer to two significant figures and include the appropriate units.
Part C) What is the ball's speed just after the bounce? Express your answer to two significant figures and include the appropriate units.
Part D) Where did the energy go?
1. The energy "lost" was changed primarily into chemical energy.
2. The energy "lost" was changed primarily into acoustic energy.
3. The energy "lost" was changed primarily into thermal energy due to friction.
4. The energy "lost" was changed primarily into heat energy.
Answer:
A) ΔEm = 0.29, B) v₁ = 5.8 m/s, c) v₂= 4.9 m / s D) the correct answer from 4
Explanation:
For this exercise we will use conservation of energy, taking care of how to choose our system
A) For this case we take two instants
starting point. When the ball goes out
Em₀ = U = m g y₁
Final point. When the ball reaches its maximum height
[tex]Em_{f}[/tex] = U = m g y₂
In this case we see that there is a loss of mechanical energy at the moment of rebound, therefore the fraction of energy lost is
ΔEm = Em_{f} / Em₀
ΔEm = mg y₂ / mg y₁
ΔEm = y₂ / y₁
ΔEm = 1.2 / 1.7
the lost part of energy
ΔEm = 1 -0.706
ΔEm = 0.29
B) the velocity just before the bounce
starting point. When the ball is released
Em₀ = U = m g y₁
final punot. Just wide of the bounce
Em_{f} = K = ½ m v₁²
As it has not yet rebounded, it has no energy loss, therefore the mechanical energy is conserved
Em₀ = Em_{f}
m g y₁ = ½ m v₁²
v₁ = √ 2 g y₁
let's calculate
v₁ =√ (2 9.8 1.7)
v₁ = 5.77 m / s
v₁ = 5.8 m/s
C) the velocity just after the bounce
starting point, after bounce
Em₀ = K = ½ m v₂²
final point. Maximum height after bounce
Em_{f} = U = m g y₂
as it already bounced, the energy is conserved in this interval
Em₀ = Em_{f}
½ m v₂² = m g y₂
v₂ = √ (2 g y₂)
v₂ = √ (2 9.8 1.2)
v₂ = 4.85 m / s
v₂= 4.9 m / s
D) during the time that the bounce lasts, there is a strong change in energy, part of it is transformed into thermal energy, due to several processes: friction, change in the potential energy of the molecules of the ball, change in the internal energy of the balls. molecules.
Therefore we cannot specify a single process, consequently the correct answer from 4
Two cars, C and D, travel in the same direction on a long, straight section of highway. During a particular time interval Ato, car D is ahead of car C and is speeding up while car C is slowing down. During the interval At, it is observed that car C gains on car D (i.e., the distance between the cars decreases). Explain how this is possible, and give a specific example of such a case.
Answer:
possibly because the car is running out of gas
Explanation:
Two tuning forks having frequencies of 460 and 464 Hz are struck simultaneously. What average frequency will you hear, and what will the beat frequency be
Answer:
462Hz, 4Hz
Explanation:
The average frequency heard would be 462 Hz because that is the average between the two and we do not hear one note more than another so the average is 462 Hz. (460+464)/2 = 462Hz. The beat frequency is basically the difference between frequencies, so our beat frequency is 464-460=4Hz.
Hope this helped!
Martin is conducting an experiment. His first test gives him a yield of 5.2 grams. His second test gives him a yield of 1.3 grams. His third test gives him a yield of 8.5 grams. On average, his yield is 5.0 grams, which is close to the known yield of 5.1 grams of substance. Which of the following are true?
Complete Question
Martin is conducting an experiment. His first test gives him a yield of 5.2 grams. His second test gives him a yield of 1.3 grams. His third test gives him a yield of 8.5 grams. On average, his yield is 5.0 grams, which is close to the known yield of 5.1 grams of substance. Which of the following are true?
A His results are accurate but not precise.
B His results are neither accurate nor precise.
C His results are both accurate and precise
D His results are precise but not accurate.
Answer:
Correct option is A
Explanation:
From the question we are told that
The yield of the first test [tex]k = 5.2 \ g[/tex]
The yield of the second is [tex]u = 1.3 \ g[/tex]
The third yield is [tex]p = 8.5 \ g[/tex]
The average yield [tex]A = 5.0 \ g[/tex]
The know yield is [tex]A_S = 5.1 \ g[/tex]
From the data given we see that
[tex]A_S \ne A[/tex]
Since his average yield is closer to the known yield then the answer is accurate
But since the yield for each test are not repeated the answer is not precise
So the answer is accurate but not precise
His results are accurate but not precise.
Your question is not complete, it seems to be missing the following information;
"A His results are accurate but not precise.
B His results are neither accurate nor precise.
C His results are both accurate and precise.
D His results are precise but not accurate."
The given parameters;
first measurement = 5.2 gsecond measurement = 1.3 gthird measurement = 8.5 gaverage measurement = 5.0known substance average yield = 5.1 gEach of the measurement is far from each other. That is 5.2 grams, 1.3 grams and 8.5 grams are all far apart. So this measurement is not precise.
The known average (5.1 g) and the measured average (5.0 g) are close to each other, so the measurement is accurate.
Thus, we can conclude that his results are accurate but not precise.
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