Option D is correct. Around the age of five, children begin to experience their first dreams and nightmares
By the time children are five years old, several developments occur in their sleep patterns.
Option A is incorrect because the typical 90-minute sleep cycles of alternating REM (Rapid Eye Movement) and NREM (Non-Rapid Eye Movement) are not yet established at this age.
Option B is also incorrect as the sleep time distribution between REM sleep and quiet sleep (similar to NREM stages 1 and 2) is not necessarily equal at this stage.
Option C is inaccurate because 60-minute sleep cycles producing up to 13 cycles per day do not align with the typical sleep patterns of five-year-olds.
However, option D is correct. Around the age of five, children begin to experience their first dreams and nightmares.
This is an important milestone in their cognitive and emotional development, as it reflects the maturation of the brain regions involved in dreaming and the processing of emotions during sleep.
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Which area of astronomy does Kepler's laws address? (1 point)
A. The movement of asteroids in the solar system
B. The movement of the sun in relation to the planets.
C. The movement of planets within the solar system.
D. The movement of stars within galaxies.
Answer:
B
Explanation:
His law describes the orbits of planets around the Sun.
The area of astronomy that Kepler's laws address is the movement of planets within the solar system. The correct option is C.
What is Kepler's law?According to Kepler's first law, "all the planets revolve in elliptical orbits around the sun, with the sun at one of the foci."
Perihelion is the point at which the planet is closest to the sun, and aphelion is the point at which the planet is farthest from the sun.
Kepler's laws of planetary motion, published between 1609 and 1619 by Johannes Kepler, describe the orbits of planets around the Sun.
Kepler's laws of planetary motion represent a watershed moment in the transition from geocentrism to heliocentrism. They establish the first quantitative link between the planets, including Earth.
Thus, the correct option is C.
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What four processes allow for the change of thermodynamics properties according to the first law
Answer:
The four types of thermodynamic process are isobaric, isochoric, isothermal and adiabatic.
help please this is due in an hour!!!
[tex]▪ ▪ ▪ ▪ ▪ ▪ ▪ ▪ ▪ ▪ ▪ ▪ ▪ { \huge \mathfrak{Answer}}▪ ▪ ▪ ▪ ▪ ▪ ▪ ▪ ▪ ▪ ▪ ▪ ▪ ▪ [/tex]
Charge on one electron :
[tex]1.602 \times 10 {}^{ - 19} \: \: coulombs[/tex]So, charge on ball having 97 electrons is equal to :
[tex]97 \times 1.602 \times 10 {}^{ - 19} [/tex][tex]155.394 \times 10 {}^{ - 19} [/tex][tex]1.554 \times 10 {}^{ - 17} \: \: coulombs[/tex]A skateboarder rolls off a horizontal ledge that is 1.32 m high and lands 1.88 m from the base of the ledge what was his initial velocity
An 80-kilogram skier slides on waxed skis along a horizontal surface of snow at constant velocity while pushing with his poles.
What is the horizontal force pushing him forward?
Answer:
Special Relativity/Newtonian Physics
Explanation:
Well in Newtonian physics you could say your mass is pushing you down and the floor is pushing you up. But rather in Special relativity only to floor is pushing up on you.
In this theory the word inertial observer matters and proves several matters throughout science. So exploring is a huge important thing to do. A person cleaning the window falls, while doing so the person feel weightless while falling. Objects that fall down with the person would remain stationarily, relative to the person. Similar to a person in space. Far away from any large masses the person would be an inertial observer. With no acceleration the person is also not close to gravitational fields and all laws of physics in the person's reference frame. The man falling off the roof is an inertial observer too. Because of this both of the matters about the rocket man and the person falling off the roof are the same.But you would think that the person falling off the roof is accelerating. But the equivalence principle tells us wrong.
The equivalence principle has made it easy to prove both people in the situations are inertial observers. People watching would think that he is accelerating, but he is not. But he is accelerating? The equivalence principle tells us to focus on the experience of the observer and the person feels weightless so they are an inertial observer. If a person in Space comes across a planet, the person's rocket will start heading towards a planet. But the Space person would be oblivious. The person would not feel any acceleration. The spaceship would not sense any acceleration nor would it sense that it is turning. A person outside the spaceship may see the slight curving motion and the person inside would not notice until the instant it crashes into the planet. Explaining this is geodesics and spacetime it equally links and connects with this in an obvious and common way.
Spacetime is a model that makes 4D, it joins space and time, ‘Space-time’. Now people can say how it perfectly describes gravity with it’s queer way of curving.
But how does this happen without gravity? Space is 4D with width, breadth, height and time. There is a model called spacetime. Einstein along with many other people visualise it as woven along with time. Space- time. It curves by mass distribution. The person is still traveling in a straight line. Just straight through spacetime. It is traveling along the geodesics of spacetime. This is actually quite common, it is just an object travelling straight on a curved surface. Like an airplane travels straight to get quicker to a different place. But it appears curved because obviously the Earth is curved. So if you unfolded the earth the path would be curved, but the plane is still traveling in a straight line. Let’s also say you and your friend were standing on the equator. You are 1000 kilometers apart from your friend. As you move towards the north direction you would eventually meet with your friend. You are not being pushed by gravity but simple as that you are just traveling on the geodesics of Earth. Matter tells spacetime how to curve, Spacetime tells matter how to move-John Wheeler.
The man falling off the roof was accelerating so what happens if the rocket man accelerates?
Now once the rocket man accelerates the floor accelerates into rocket man. Objects remain stationary but the floor also accelerates into the objects. The situation is just like on earth except you are not an inertial observer because you do not feel weightless. The observer inside the rocket would feel a force pushing up on the feet. Same on earth. You are accelerating in order to remain stationary. However you can not see yourself accelerating. In Newton’s rule the force of Gravity would be pushing you down and the ground pushing you up. However in special relativity gravity does not exist so it’s just the force of the ground pushing up on you. Just like the rocket accelerating. You look like you are not accelerating up but only in your frame of reference. To measure your speed of acceleration you must get an inertial observer to measure your acceleration speed. Like the man falling off the roof. Let’s say you are in the building and the man falls off the roof. To him you would appear accelerating upwards. So you have to accelerate just to stand still. Why all objects fall at the same rate is a mystery to Newtonian Physics but it is not a mystery to Special relativity because the objects are not accelerating just the floor accelerating into it.
So I hope you understand now, I think you know what I'm getting at. Might of misunderstood your question.
When the propeller were turning at 25 rad/s , what is the period (in seconds) of this propeller?
Answer:
Explanation:
T = (2π rad / rev) / (25 rad/s) = 0.251327... = 0.25 s
The propeller was turning at 25 rad/s then the period of the propeller will be equal to 0.25 seconds.
What is Velocity?In terms of physics, velocity is a vector assessment of the motion's direction and speed. The rate of change in an object's position relative to a reference frame and time is the more precise definition of velocity. Simply put, the concept of velocity informs us of the rate at which an object is travelling in a given direction.
It indicates the rate of motion of objects. Take two moving things like our illustration. If both items are travelling in the same vague direction, it is simple to determine which is moving more quickly.
From the given data in the question,
T = 2π (rad/rev) / 25 (rad/s)
T = 0.25 seconds.
Therefore, the period of this propeller is 0.25 seconds.
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A rock is held steady over a cliff and dropped. 1 seconds later, another rock is thrown straight down at a speed of 11.3 m/s, and hits the first rock. How far have the rocks dropped before they collide? How long is the first rock in the air before it gets hit by the second rock?
What is the displacement of the rocks when they collide? __________ (Hint: be careful of sign -- the rocks drop.)
The first rock is in the air for __________ before it is hit.
Answer:
4.27s
Explanation:
If "t" represents the time traveled from the time rock 2 is dropped until the collision, then the time traveled for rock 1 = t + 1. And, since rock #1 is dropped making its initial velocity = 0, then:
The distance rock 1 travels is
x = (0)(t + 1) + 1/2(-9.8)(t + 1)2 = -4.9(t2 + 2t + 1) = -4.9t2 - 9.8t - 4.9
The distance rock 2 travels
x = -11.3t + 1/2(-9.8)t2 = -11.3t - 4.9t2
For the distances must be equal when the rocks collide:
-4.9t2 - 9.8t - 4.9 = -11.3t - 4.9t2
-9.8t - 4.9 = -11.3t
-4.9 = -1.5t
t = 3.267 s
Now, the distance they traveled can be found by plugging the 3.267 s back into either equation:
x = -11.3(3.267) - 4.9(3.267)2 = -89.2 m or 89.2 m below where they began
The time the first rock was in the air is t + 1 = 3.267 + 1 = 4.267 s = 4.27 s
Let
First rocks time be x
Second rocks time be x+1
initial velocity=u=11.3m/s
Distance of both rocks be s1 and s2
[tex]\\ \sf\longmapsto s=ut+\dfrac{1}{2}at^2[/tex]
Now
[tex]\\ \sf\longmapsto s1=11.3x+5x^2[/tex]
[tex]\\ \sf\longmapsto s2=11.3(x+1)+5(x+1)^2[/tex]
As both collide then
[tex]\\ \sf\longmapsto s1=s2[/tex]
[tex]\\ \sf\longmapsto 11.3x+5x^2=11.3x+11.3+5(x+1)^2[/tex]
[tex]\\ \sf\longmapsto 5x^2=11.3+5x^2+10x+1[/tex]
[tex]\\ \sf\longmapsto 10x+12.3=0[/tex]
[tex]\\ \sf\longmapsto x=1.23s[/tex]
Displacement
[tex]\\ \sf\longmapsto 11.3(1.23)=13.8m[/tex]
Done
What is the pulling force of this train, if its engine provides 4200 kW power and 90 km/h speed?
Answer:
yes by 30
Explanation:
uhnhuh
Which of the following statements is false about photosynthesis and cellular respiration?
O Photosynthesis uses carbon dioxide.
O Cellular respiration gives off carbon dioxide.
O Photosynthesis makes glucose.
O Both photosynthesis and cellular respiration occur in all living things.
Answer:
photosynthesis uses carbon dioxide
Explanation:
Consider the following statements:
1. Carbon dioxide, chlorophyll, and sunlight are all essential for photosynthesis.
2. Rate of photosynthesis is maximum in red light and minimum in green light.
3. Increase
concentration decreases the rate of photosynthesis.
Which of the statements given above are correct about photosynthesis?
You are driving to grandma's house, and you are traveling at an average of 70 mph. How long will it take you to travel 70 miles?
O 1 hour
O 1 second
70 hours
O 70 seconds
Answer: 1 hour
Explanation: Focus on the units; 70 miles per hour means that each hour, you will travel 70 miles
or you can use the equation time = distance/speed. You have 70miles/ 70mph = 1hour
Elvis and Noah want to move the piano in their living room. Elvis pushes from behind with a force of
400 N, and Noah pulls from the front using a rope with a force of 150 N. The piano has a mass of 225 kg,
and the friction force of the floor and the piano is 100 N.
Calculate the acceleration of the piano.
Round your answer to the nearest tenth.
Answer:
2.0 m/s
Explanation:
Remember that F = maF=maF, equals, m, a, where FFF is the net force, mmm is the mass of the object, and aaa is its acceleration. To solve this problem, we will need to first find the net force acting on the piano and then use F = maF=maF, equals, m, a to find the piano’s acceleration.
Hint #22 / 4
The net force is the sum of all of the forces on the piano. In this circumstance, Elvis's and Noah's forces are in the same direction, and the friction force is in the opposite direction. So, our net force equation would be:
=400 N+150 N−100 N
=450 N
Now, we can use F = maF=maF, equals, m, a and solve for the acceleration:
225 kg
450 N
=2.0
The acceleration of the piano is 2.0 m/s
The acceleration of the piano is 2m/s².
We know the formula for force is
F =ma
where f is force, m is mass and a is acceleration.
We need to calculate the total force used in moving the piano
F= Total force- Frictional force
F= 400N+150N-100N= 450N.
We have F=450N and m= 225kg
F=ma
450N= 225ˣ a
a= 450/225
a= 2m/s²
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Aluminum foil crunched between teeth with gold fillings (which one is negatively charged and which one is positively charged?)
Answer:
Aluminum foil is negatively charged and gold fillings are positively charged.
Hope this helps :)
Michael stands upright and allows his right arm to swing back and forth, naturally and without forcing, like a pendulum. He measures the time for 21 oscillations (complete cycles) to be 28.1 s. Assume his arm (length L) behaves as a simple pendulum, with an effective length of 2/3 L. Find the length of his arm, L.
Answer:
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The length of his arm, L = 0.67 m.
What is time period?
A basic pendulum consists of a point mass hung by a tightly supported, weightless, and inextensible string.
T = 2π√ L/g, where L is the pendulum's length and g is the acceleration brought on by gravity, is the formula for a pendulum's period.
Given in the question the time for 21 oscillations (complete cycles) to be 28.1 s. Assume his arm (length L) behaves as a simple pendulum, with an effective length of 2/3 L.
T = 2π√ L/g
T = 2π√2l/3g
T = 28.1/21
T = 1.33
2π√2l/3g = 1.33
l = .67 m
The length of his arm, L = 0.67 m.
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During a certain period of time, the speedometer of a car reads a constant
60 km/h. Does this indicate a constant speed? A constant velocity?
A train travels meters in the first second of travel, 6 meters again during the second second of travel, and 6 meters again during the third second. Its
acceleration is
O 0 m/s
6 m/s
O 12 m/s/s
18 m/s
O None of the above
Answer:
0 m/sExplanation:
there is no acceleration, it's velocity is always 6m/s
so your answer is 0m/s
the position of an ant and a spider in a room are A(2,3,5) and B(6,0,8) determine the distance
Answer:
[tex] |d| = \sqrt{ {(x_{2} -x_{1})}^{2} + {(y_{2} -y_{1})}^{2} + {(z_{2} -z_{1})}^{2}} \\ = \sqrt{ {(6 - 2)}^{2} + {(3 - 0)}^{2} +{(5 - 8)}^{2} } \\ = \sqrt{16 + 9 + 9} \\ = \sqrt{34} [/tex]
The position of an ant and a spider in a room are A(2,3,5) and B(6,0,8) the distance between ant and spider is 5.83 m.
What is Distance between two points?The distance formula states that the distance between two points in xyz-space is the square root of the sum of the squares of the differences between corresponding coordinates A( [tex]x_{1}[/tex] , [tex]y_{1}[/tex] , [tex]z_{1}[/tex] ) and B( [tex]x_{2}[/tex] , [tex]y_{2}[/tex] ,[tex]z_{2}[/tex]),
AB² = ([tex]x_{2}[/tex] - [tex]x_{1}[/tex])² + ([tex]y_{2}[/tex] - [tex]y_{1}[/tex])² + ( [tex]z_{2}[/tex] - [tex]z_{1}[/tex] )²
In reality, the Pythagorean Theorem is nothing more than the distance formula. Draw a right triangle using the segment AB as its hypotenuse in order to get the distance AB between points A( [tex]x_{1}[/tex] , [tex]y_{1}[/tex] ) and B( [tex]x_{2}[/tex] , [tex]y_{2}[/tex] ).
Given that in the question two points are A(2,3,5) and B(6,0,8), so the distance between them is
AB² = ([tex]x_{2}[/tex] - [tex]x_{1}[/tex])² + ([tex]y_{2}[/tex] - [tex]y_{1}[/tex])² + ( [tex]z_{2}[/tex] - [tex]z_{1}[/tex] )²
AB² = 4² + 3² + 3²
AB² = 34
AB = 5.83 m
Position of an ant and a spider in a room are A(2,3,5) and B(6,0,8) the distance between ant and spider is 5.83 m.
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The Sun's primary energy source is
Answer:
nuclear fusion
Explanation:
converting hydrogen to helium.
A rocket traveling through space with a constant velocity of 10 m/s fires up a booster. The booster accelerates the rocket at a rate of 5 m/s. What distance in meters has the rocket traveled within 12 seconds after the booster is turned on?
The distance traveled by the rocket after the given time period is 480 m.
The given parameters;
velocity of the rocket, v = 10 m/sacceleration of the rocket, a = 5 m/s²time of motion of the rocket, t = 12 sThe distance traveled by the rocket after the given time period is calculated from the second kinematic equation of as shown below;
s = ut + ¹/₂at²
s = (10 x 12) + (0.5 x 5 x 12²)
s = 120 + 360
s = 480 m
Thus, the distance traveled by the rocket after the given time period is 480 m.
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A ball rolls with a constant acceleration of 2.5 m/s^2 for 5.0 s with an initial velocity of 5.0 m/s. Calculate the
ball's distance from the starting point at 1.0 s intervals. Make a position-time graph for the object's motion. In
your response, show what you are given, the equation that you used, any algebra/work required, a table of
data, and your graph.
The kinematics allows finding the answers for the positions of the body as a function of time and making its graph are:
The positions according to time are in the table In the attachment we can see a graphic representation
Given parameters
The acceleration a = 2.5 m / s² Time t = 5.0 s The initial velocity vo = 5.0 m / sTo find
The distance each Dt = 1.0 s
Kinematics studies the motion of bodies, gives relationships between the position, velocity and acceleration of bodies, let's use the relationship
x = v₀ t + ½ a t²
Where x is the position, v or the initial velocity, at the acceleration and t is the time.
Let's substitute
x = 5 t + ½ 2.5 t²
x = 5 t + 1.25 t²
Let's calculate the position and write it in the table
t = 0 s x = 0 m
t = 1 s x = 5 1 + 1.25 1² = 6.25 m
t = 2 s x = 5 2 + 1.25 2² = 15 m
t = 3s x = 5 3 + 1.25 3² = 26.25 m
t = 4 s x = 5 4 + 1.25 4² = 40 m
t = 5 s x = 5 5 + 1.25 5² = 56.25 m
In the following table the time and positions of the body are given, these given are used for the attached graph
time (s) position (m)
0 0
1 6.25
2 15
3 26.25
4 40
5 56.25
In conclusion, using kinematics we can find the answers for the positions of the body as a function of time and make its graph are:
The positions according to time are in the tableIn the attachment we can see a graphic representation
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quá trình nào entropi của hệ không đổi
Answer:
I don speak communism. Could you answer in English?
Explanation:
Why are the alkali metals likely to react with group 17 elements?
Answer:
Because alkali metals are so reactive, they are found in nature only in combination with other elements. They often combine with group 17 elements, which are very “eager” to gain an electron.
Explanation:
hope this helps you if it does please mark brainliest
When a car's acceleration is negative, what is happening to the car's motion?
the car slows down
the car speeds up
the car travels at a constant speed
the car remains at rest
Answer:
the car slows down
Explanation:
Please help, I need this in by today
What is the magnitude of the momentum of a 1000 kg car traveling
at 5 m/s?
Answer:
5000 kg.m/sExplanation:
The momentum of an object can be found by using the formula
momentum = mass × velocity
From the question
mass = 1000 kg
velocity = 5 m/s
We have
momentum = 1000 × 5 = 5000
We have the final answer as
5000 kg.m/sHope this helps you
What is the smallest part of a compound called?
element
O
molecule
O
atom
O
mixture
o
Answer:
Here is your answer,thanks for using brainly!
Explanation:
B:Molecule
Molecules usually consist of 2 atoms linked together,however some molecules consist of thousands of atoms!
Here is a list of smalles to largest with the answers provided
Molecules
Atoms
Elements
Mixtures
Hope this helped
Plz mark brainliest
Dont forget to smash that heart at the bottom <3
Have a great day!
Find out which of the following sentences is a false statement. Group of answer choices The potential energy of a pair of positively charged bodies is positive. The potential energy of a pair of oppositely charged bodies is negative. The total work required to assemble a collection of discrete charges is the electrostatic potential energy of the system. The potential energy of a pair of negatively charged bodies is negative. The potential energy of a pair of oppositely charged bodies is positive.
The statements which are false from the choices above are:
The potential energy of a pair of negatively charged bodies is negativeThe potential energy of a pair of oppositely charged bodies is positiveIn scenarios of like charges, the potential energy is always positive, that is because we need to put energy in the system to bring like charges closer together.
Conversely, for unlike charges, the potential energy of the pair of unlike charges is negative, as a result of the energy expended by the system in pushing the charges away from each other.
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A rod is heated at the rate of 30 watts at the middle point and is insulated at its two ends. The two half sections are cooled by convection by an ambient fluid at 20 degree Celsius with a heat transfer coefficient of 30 W/m^2 C. The diameter of the rod is 0.5 cm, its length is 18 cm and its thermal conductivity is 206 W/mC. Determine the temperature in the middle of the rod and at the insulated ends. Please describe your strategy of solving this problem.
thanks for the points
Explanation:
While you push a box you begin to decrease the force you are exerting on the box. When will the box reach equilibrium?
A. When the force you are exerting on the box is equal to 0.
B. When Fyou on box = -Fbox on you.
C. When the force of the box becomes Fyou on box < Fbox on you
D. The box will never reach equilibrium.
The application of a force on the box overcomes the friction and causes the box to accelerate
While the force is decreasing, the box will stabilize;
B. When [tex]\underline{F_{you \, on \, box} = -F_{box \, on \, you}}[/tex]Reason:
Newton's third Law of Motion states that action and reaction are equal in magnitude and opposite in direction
When the box is pushed with a force, [tex]F_{you \, on \, box}[/tex], the reaction of the box of mass, m, is as follows;
[tex]F_{you \, on \, box}[/tex] = [tex]F_{friction}[/tex] + m × accelerationWhere;
[tex]F_{friction}[/tex] = [tex]-F_{box}[/tex] for example
The negative sign is due to the direction of the friction force, or [tex]F_{box}[/tex] is opposite to the direction of the applied force
When the force is decreased to F₂ = [tex]F_{you \, on \, box}[/tex], such that we have;
[tex]F_{you \, on \, box}[/tex] = [tex]-F_{box \, on \, you}[/tex] , which is the condition for equilibrium, and the net
force is zero and according to Newton's first law of motion, the box moves
at constant speed no acceleration
Therefore the box will reach equilibrium when;
[tex]\mathbf{\underline{F_{you \, on \, box} = -F_{box \, on \, you}}}[/tex]Learn more about equilibrium here;
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Answer:
When the force you are exerting on the box is equal to 0
Explanation:
Once again expert verifiers are sabotaging people here is the actual answer.
In two paragraph of lines each, describe how you
would simplify, for your
grade 10 learners the
following topics
1.1 Electricity and magnetism.
The question above wants to assess your ability to simplify complex matters. In that case, I can't answer this question for you, but I'll show you how to answer it.
First, you should research electricity and magnetism. This research will make you understand the subject and all its elements. You can do this research in textbooks and digital platforms aimed at children and teenagers since these media usually present subjects in a more simplified way.
After doing this research, you will be able to write a text about electricity and magnetism as follows:
Present the main focus of this subject.Present the elements that make up this subject.Present how this subject applies in the real world.Present the importance of this subject in human life and society.Remember that you must use simple language, without the use of technical terms, but with common terms.
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An engine raises 120kg of water through a height of 40m in 30s.What is the power of the engine take gravity to be = 10m/s.
Answer:
1600 W
Explanation:
Power is the product of force and distance, divided by time.
P = (120 kg)(10 m/s²)(40 m)/(30 s) = 1600 kg·m²/s³ = 1600 W