A child is standing in the center of a rotating platform and then walks toward the outside edge. Describe the change in the child-platform system, if any, of each of the following quantities. Justify your answers. • Angular momentum
• Rotational inertia • Angular velocity • Rotational kinetic energy
Answers
When the child moves from the center to the edge of the rotating platform, the following changes occur in the child-platform system: 1. Angular momentum, 2. Rotational inertia, 3. Angular velocity and 4. Rotational kinetic energy.
1. Angular momentum: Remains constant. Angular momentum is conserved in the absence of external torque, so the total angular momentum of the child-platform system does not change.
2. Rotational inertia: Increases. As the child moves away from the center, the distance between the child and the rotation axis increases, which leads to an increase in the moment of inertia (rotational inertia) of the system.
3. Angular velocity: Decreases. Due to the conservation of angular momentum (L = Iω, where L is angular momentum, I is rotational inertia, and ω is angular velocity), as rotational inertia increases, angular velocity must decrease to keep the product constant.
4. Rotational kinetic energy: Remains constant. Since the total angular momentum is conserved, and rotational kinetic energy is proportional to the square of angular velocity and rotational inertia (K = 1/2 Iω^2), the changes in angular velocity and rotational inertia result in no net change in rotational kinetic energy.
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Related Questions
What is the relationship between frequency and wavelength?
Answers
Answer:
Frequency and wavelength are inversely proportional to each other. The wave with the greatest frequency has the shortest wavelength. Twice the frequency means one-half the wavelength.
Explanation:
if the snow is level at the foot of the incline and has the same coefficient of friction, how far will the ski travel along the level? use energy methods.
Answers
The ski will travel a distance of (2μL/3) + (2/3)h along the level at the foot of the incline.
Assuming that the ski starts from rest at the top of the incline and slides down the incline without any loss of energy due to friction or air resistance, the potential energy of the ski at the top of the incline is converted entirely into kinetic energy as it slides down the incline. When the ski reaches the bottom of the incline, all of the kinetic energy is transferred into potential energy and frictional work done by the coefficient of friction, bringing the ski to a stop.
Let's denote the height of the incline by h, the length of the incline by L, and the coefficient of friction between the ski and the snow by μ.
The potential energy of the ski at the top of the incline is given by:
PE = mgh
where m is the mass of the ski and g is the acceleration due to gravity. At the bottom of the incline, the potential energy is zero, and the kinetic energy of the ski is given by:
KE = (1/2)m\(v^2\)
where v is the speed of the ski at the bottom of the incline.
Since there is no net work done on the ski by external forces, the total energy of the ski is conserved, i.e.,
PE(top of incline) = KE(bottom of incline) + Work(friction)
mgh = (1/2)m\(v^2\) + μmgd
where d is the distance traveled by the ski along the level at the foot of the incline. Since the ski starts from rest at the top of the incline, we can also use the equation:
\(v^2\) = 2gh
To eliminate v from the above equation, giving:
d = (2μL/3) + (2/3)h
Therefore, the ski will travel a distance of (2μL/3) + (2/3)h along the level at the foot of the incline.
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If a train travels 25 miles in 2 hours 15 minutes, what is its average speed in miles per hour? 11. 1 mph 12. 5 mph 10 mph 9. 1 mph.
Answers
Answer:
11.1
Explanation:
2 hours 15 mins = 2 1/4 hours
2 1/4 hours = 25 miles
1 hour = 25 ÷ 2 1/4 = 25 ÷ 9/4 = 25 x 4/9 = 11.1 miles
URGENT! i don't understand how displacement works and it'd be nice if you could also show steps on how to do it:( THank you!
Calculate the total displacement of a mouse walking along a ruler, if it begins at the x=5cm, and then does the following:
It walks to x=12cm
It then walks a displacement of -8cm
Lastly, it walks to the location x=7cm
Answers
7-5 =2
so the mouse would’ve walked a displacement of 2cm
A stone is thrown horizontally at 15 m/s from the top of a cliff. It takes it 2.4 s to hit the ground. How far from the base of the cliff does the stone hit the ground
Answers
Distance=Speed*Time
Distance=15*2.4
Distance=36m
An unknown force is applied to a 12 kg mass. The force acts at an angle of 30.0 degrees above the horizontal. Determine the force acting if the force acts for a horizontal displacement of 22 meters and increases the 12 kg mass's speed from 11 m/s to 26 m/s.
Answers
The mass undergoes a change in kinetic energy of
∆K = 1/2 (12 kg) [(26 m/s)² - (11 m/s)²] = 3330 J
By the work-energy theorem, the total work W performed on the mass is equal to ∆K. Assuming no friction, only the horizontal component of the applied force performs work on the mass.
Let F be the magnitude of this force, so that its horizontal component has mag. F cos(30.0°) = √3/2 F. It acts over a displacement of 22 m and performs 3330 J of work in the process, so that
3330 J = (√3/2 F) (22 m) ⇒ F = 1110√3/11 N ≈ 175 N
A 1.50 kg cart moves in a circular path of 1.30 m radius at a constant speed of 2.00 m/s. (a) Calculate the magnitude of the centripetal acceleration of the cart.
(b) Calculate the magnitude of the centripetal force on the cart.
(c) Calculate the coefficient of friction between the tires and the ground
(d) Describe the direction of the centripetal force.
Answers
Answer:
the answer is 1500 because of the internet
Muscular strength allows you to?
Answers
Answer:
Carry out daily activities
Explanation:
lift heavy objects,
walk,
look fit for the ladies.
how the HSR works in China?
Answers
Answer:
High-speed rail in China is officially defined as "newly-built passenger-dedicated rail lines designed for electrical multiple unit (EMU) train sets traveling at not less than 250 km/h (155 mph) (including lines with reserved capacity for upgrade to the 250 km/h standard) on which initial service operate at not less ...
29.In which of the following pictures is the average kinetic energy of molecules the highest?Select one:a. Ab. Bc. Cd. D
Answers
We will have that the picture that shows the highest average kinetic energy is image B.
The pecific heat of a liquid X i 2. 09 cal/gC. A ample gram of thi liquid at 101 K i heated to 225K. The liquid aborb 5. 23 jack. What i the ample of liquid in gram?
Answers
The amount of sample of liquid in grams when its temperature is raised is calculated to be 20 g.
The term specific heat capacity refers to the amount of heat needed to raise a substance's temperature by one degree Celsius.
Q = m c Δt
Q = 5.23 kcal of heat are absorbed by fluids = 5230 cal
C = heat capacity of liquid = 2.09 cal/g °C
Initial temperature of the liquid T i = 101 K
Final temperature of the liquid T f = 225 K
Change in temperature, Δt = T f - T i = 225 - 101 K = 124 K
Putting in the values, we get:
5230 = m × 2.09 cal/g °C × 124 K
m = 20 g
The given question is incomplete. The complete question is 'The specific heat of a liquid x is 2.09 cal/g°c. A sample amount of grams of this liquid at 101 k is heated to 225 k. the liquid absorbs 5.23 k cals. what is the sample of liquid in grams? (round off decimal in the answer to nearest tenths)'
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The minute hand of a clock completes one revolution in one hour. There are 3,600 seconds in one hour. Calculate the frequency of the minute hand
Answers
The frequency of the minute hand is 1/60 Hz. Given that the minute hand of a clock completes one revolution in one hour and there are 3,600 seconds in one hour.
To calculate the frequency of the minute hand: Frequency of the minute hand = No. of revolutions per secondFirstly, let us calculate the number of revolutions of the minute hand in one second.1 hour = 60 × 60 = 3600 secondsIn one hour, the minute hand completes 1 revolution. So, in 1 second, the minute hand completes 1/3600 of the revolution.Now, we can calculate the frequency of the minute hand.
Frequency of the minute hand = No. of revolutions per second Frequency of the minute hand = 1/3600 HzTo calculate the frequency of the minute hand, we can use the following steps: Step 1: Calculate the number of revolutions of the minute hand in one second.1 hour = 60 × 60 = 3600 seconds In one hour, the minute hand completes 1 revolution.
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What is one problem that you think needs to be solved so that your future is safer for your children?
Answers
Answer:
Systemic racism
Explanation:
PLZ HELP, GIVING BRAINLIEST!!
A student uses a 320 Hz tuning fork during a lab investigation into the speed of sound. If the air temperature in the classroom is 20 degrees Celsius, what is the wavelength of the sound waves produced by the tuning fork?
A. 1.07 m
B. 3.43 m
C. 0.933 m
D. 343 m
E. 343 m
Answers
Answer:343m
Explanation:
Please help I will mark brainliest
Answers
Answer:
1.) B
2.) Polar Regions or high altitudes.
Explanation:
Acceleration due to gravity is 9.8 m/s2 on the surface of Earth, and at orbits 200 miles above the surface of Earth, where the space shuttle orbits, the acceleration is
Answers
Acceleration due to gravity is 9.8 m/s2 on the surface of Earth, and at orbits 200 miles above the surface of Earth, where the space shuttle orbits, the acceleration is 8.78 m/s².
What is gravitational force?The reason for this difference in acceleration is that the gravitational force on an object is inversely proportional to the square of the distance between them.
Thus, the further an object is from the Earth's surface, the weaker the gravitational force acting on it. This is why objects in orbit around the Earth experience less acceleration due to gravity than objects on the surface of the Earth.
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Using the video controls to advance and rewind, compare the wave shape of an alligator’s low-frequency mating call with the wave shape of a frog’s high-frequency chorus. How are the shapes different?
Answers
When compared, the low-frequency waves of the alligator are stretched out, while the high-frequency shapes of the frogs are very close together.
What are the other differences between low-frequency and high-frequency waves?The fewer the oscillations, the lower the frequency. Oscillations are more common at higher frequencies. The frequency units are known as hertz (Hz). Humans with typical hearing can detect noises at frequencies ranging from 20 to 20,000 hertz.
A wave's frequency is inversely proportional to its wavelength. That is, high-frequency waves have a short wavelength, whereas low-frequency waves have a greater wavelength. The wavelengths of light waves are quite short.
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A hockey puck has a coefficient of kinetic friction of = .20. If the puck feels a normal force of 5 N, what is the frictional force that acts on the puck?
Answers
Answer: 5 N
Explanation:
Friction is a force that prevents two solid objects from rolling or sliding over one another. Although frictional forces, like the traction required to walk without slipping, may be advantageous, they also pose a significant amount of resistance to motion.
The given parameters;
coefficient of kinetic friction, μk = 0.1normal force of the puck, Fₙ = 5 NBy multiplying the normal force and the coefficient of kinetic friction, the frictional force acting on the puck is calculated.
The frictional force that acts on the puck is calculated as follows;
F= u*f
Substitute the given parameters in the above equation and solve the frictional force.
F=0.2*5
F= 1 N
Thus, the frictional force that acts on the puck is 1 N.
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How do textures of objects affect the friction produce when two objects
are in contact with each other?
Answers
We can see here that the textures of objects play a significant role in determining the friction produced when two objects are in contact with each other.
What is friction?Friction is a force that opposes the relative motion or attempted motion between two surfaces in contact. When two objects are in contact and one tries to slide, roll, or move past the other, friction acts in the opposite direction to resist or impede that motion.
Here's how different textures affect friction:
Rough Surfaces: Objects with rough surfaces tend to have more friction when in contact with each other. Smooth Surfaces: Objects with smooth surfaces have less friction when in contact with each other.Learn more about friction on https://brainly.com/question/24338873
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Which of the following feedbacks are definitely positive (that is, there is no uncertainty that they are positive)? [select all that apply] Laspe rate feedback Water vapor feedback Ice albedo feedback Cloud feedback Question 4 1 pts Which of these feedbacks affect the terrestrial radiation budget? [select all that apply] Lapse rate feedback Ice-albedo feedback Water vapor feedback Cloud feedback
Answers
The positive feedbacks without uncertainty are water vapor feedback. The feedbacks that affect the terrestrial radiation budget are lapse rate feedback, ice-albedo feedback, water vapor feedback, and cloud feedback.
Among the feedbacks listed, the ones that are definitely positive (without uncertainty) are: 1. Water vapor feedback: An increase in temperature leads to an increase in atmospheric water vapor content, which amplifies the greenhouse effect and further enhances warming. This feedback is positive. The feedbacks that affect the terrestrial radiation budget (the balance of incoming and outgoing radiation at the Earth's surface) are: 1. Lapse rate feedback: This feedback is related to the vertical temperature profile of the atmosphere. If the lapse rate (the rate at which temperature changes with altitude) decreases with warming, it can amplify the warming or cooling effects. It affects the radiation budget indirectly by influencing the atmospheric temperature structure. 2. Ice-albedo feedback: When temperatures rise, ice and snow cover decrease, exposing darker surfaces (such as land or ocean) that absorb more solar radiation. This leads to further warming, creating a positive feedback loop that affects the radiation budget. 3. Water vapor feedback: As mentioned earlier, an increase in temperature leads to increased atmospheric water vapor content. Water vapor is a potent greenhouse gas that affects the radiation budget by trapping outgoing longwave radiation and amplifying the greenhouse effect.b4. Cloud feedback: Changes in temperature and atmospheric moisture content can affect cloud formation and properties. Clouds can either trap heat (positive feedback) or reflect sunlight back to space (negative feedback), depending on their type, altitude, and coverage. The net effect of cloud feedback on the terrestrial radiation budget depends on the specific cloud changes in response to warming.
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The sides of a rectangle are 6.01 meters and 12 meters. Taking the significant figures into account, what is the area of the rectangle? A. 70 square meters B. 72 square meters C. 72.00 square meters D. 72.1 square meters
Answers
Answer:
D. 72.1 m^2
Explanation:
6.01m x 12m = 72.12 m^2
A skydiver is descending towards the earth with her parachute open. The work done by the drag force from the air is A) 0 B) Positive C) Negative
Answers
The work done by the drag force from the air is negative
When a skydiver descends towards the earth with a parachute open, there are two main forces acting on the skydiver: the gravitational force pulling the skydiver towards the earth and the drag force from the air resistance acting in the opposite direction to the motion. The drag force is proportional to the velocity of the skydiver and is directed opposite to the velocity vector. As the skydiver descends, the velocity decreases, and so does the magnitude of the drag force.
The work done by a force is defined as the product of the force and the displacement of the object in the direction of the force. In the case of the drag force acting on the skydiver, the direction of the force is opposite to the direction of the displacement.
In other words, as the skydiver descends, the drag force from the air resistance does negative work on the skydiver, which means that it reduces the kinetic energy of the skydiver. This is why a skydiver gradually slows down as they approach the ground, even with an open parachute.Therefore, the work done by the drag force is negative.
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what process does the sun use to generate heat and light?
Answers
Solar energy is created by nuclear fusion that takes place in the sun. Fusion occurs when protons of hydrogen atoms violently collide in the sun's core and fuse to create a helium atom. This process, known as a PP (proton-proton) chain reaction, emits an enormous amount of energy.
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Which of the following is the best example of a heat conductor?
Answers
Answer:
Anything with a dark shade in color and with no reflective surface or any metalExplanation:
In this case, a dark shirt or blanket would be a heat conductor as well as metal would be, too
If you stand 50 cm from a plane mirror, where is your image?
Answers
Answer:
100 cm away from you
Explanation:
Found a good example demonstrating this problem I think:
In the space provided, sketch and label a graph of the angular velocity as a function of time, including labels on the axes, standard units, a title, and if applicable, any significant numerical values.
Answers
Theta = position angle, t = time, and w = angular velocity, where w = angular velocity, theta = position angle, and t = time. Angular velocity is the rate of change of an object's position angle with respect to time.
Thus, An object's rate of rotation and direction of rotation are both described by its angular velocity.
It is customary for the positive direction to be in the counterclockwise direction. Here are some angular velocity issues for practice. The ratio of the angular displacement () to the time of motion, for a constant angular velocity, is the angular velocity.
Angular velocity only applies to things that are moving in a circular motion, making it less frequent than linear velocity.
A racecar on a circular track, a roulette ball on a wheel, or a Ferris wheel are a few examples of objects with angular motion.
Thus, An object's rate of rotation and direction of rotation are both described by its angular velocity.
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A machine has mechanical advantage 2,what does it mean?
Answers
Answer:
The mechanical advantage of a machine is 2. Mechanical advantage MA is the ratio of output (generated by the machine) force to input (applied to the machine) force. So MA = 2 means that for example if you apply 100 N then your machine will multiply that force and generate 200 N .
The pressure regulator valve keeps the pressure at a regulated level by exhausting excess pressure back to the _________________.
Answers
The pressure regulator valve is responsible for maintaining a regulated level of pressure. When the pressure exceeds the desired level, the valve exhausts the excess pressure back to the source.
To better understand this concept, let's use an analogy. Imagine a balloon being filled with air. As the air pressure inside the balloon increases, it reaches a certain point where it becomes too high, risking the balloon's rupture.
In this scenario, the pressure regulator valve acts like a safety mechanism. It senses the excessive pressure and releases some of the air back into the environment, ensuring that the balloon remains intact.
Similarly, in various systems such as pneumatic or hydraulic systems, the pressure regulator valve monitors the pressure and prevents it from exceeding a predetermined level.
By opening a pathway for the excess pressure to escape, the valve helps maintain a safe and regulated pressure, protecting the system from damage.
In summary, the pressure regulator valve exhausts excess pressure back to the source or the environment, ensuring that the pressure remains within a safe and regulated range.
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yes that.
Read the excerpt below and then answer the question that follows:
The Book of Dragons
Chapter III The Deliverers of Their Country, an excerpt
By E. Nesbit
It all began with Effie's getting something in her eye. It hurt very much indeed, and it felt something like a red-hot spark—only it seemed to have legs as well, and wings like a fly. Effie rubbed and cried—not real crying, but the kind your eye does all by itself without your being miserable inside your mind—and then she went to her father to have the thing in her eye taken out. Effie's father was a doctor, so of course he knew how to take things out of eyes.
When he had gotten the thing out, he said: "This is very curious." Effie had often got things in her eye before, and her father had always seemed to think it was natural—rather tiresome and naughty perhaps, but still natural. He had never before thought it curious.
Effie stood holding her handkerchief to her eye, and said: "I don't believe it's out." People always say this when they have had something in their eyes.
"Oh, yes—it's out," said the doctor. "Here it is, on the brush. This is very interesting."
Effie had never heard her father say that about anything that she had any share in. She said: "What?"
The doctor carried the brush very carefully across the room, and held the point of it under his microscope—then he twisted the brass screws of the microscope, and looked through the top with one eye.
"Dear me," he said. "Dear, dear me! Four well-developed limbs; a long caudal appendage; five toes, unequal in lengths, almost like one of the Lacertidae, yet there are traces of wings." The creature under his eye wriggled a little in the castor oil, and he went on: "Yes; a bat-like wing. A new specimen, undoubtedly. Effie, run round to the professor and ask him to be kind enough to step in for a few minutes."
"You might give me sixpence, Daddy," said Effie, "because I did bring you the new specimen. I took great care of it inside my eye, and my eye does hurt."
The doctor was so pleased with the new specimen that he gave Effie a shilling, and presently the professor stepped round. He stayed to lunch, and he and the doctor quarreled very happily all the afternoon about the name and the family of the thing that had come out of Effie's eye.
But at teatime another thing happened. Effie's brother Harry fished something out of his tea, which he thought at first was an earwig. He was just getting ready to drop it on the floor, and end its life in the usual way, when it shook itself in the spoon—spread two wet wings, and flopped onto the tablecloth. There it sat, stroking itself with its feet and stretching its wings, and Harry said: "Why, it's a tiny newt!"
The professor leaned forward before the doctor could say a word. "I'll give you half a crown for it, Harry, my lad," he said, speaking very fast; and then he picked it up carefully on his handkerchief.
"It is a new specimen," he said, "and finer than yours, Doctor."
It was a tiny lizard, about half an inch long—with scales and wings.
So now the doctor and the professor each had a specimen, and they were both very pleased. But before long these specimens began to seem less valuable. For the next morning, when the knife-boy was cleaning the doctor's boots, he suddenly dropped the brushes and the boot and the blacking, and screamed out that he was burnt.
And from inside the boot came crawling a lizard as big as a kitten, with large, shiny wings.
"Why," said Effie, "I know what it is. It is a dragon like the one St. George killed."
And Effie was right. That afternoon Towser was bitten in the garden by a dragon about the size of a rabbit, which he had tried to chase, and the next morning all the papers were full of the wonderful "winged lizards" that were appearing all over the country. The papers would not call them dragons, because, of course, no one believes in dragons nowadays—and at any rate the papers were not going to be so silly as to believe in fairy stories. At first there were only a few, but in a week or two the country was simply running alive with dragons of all sizes, and in the air you could sometimes see them as thick as a swarm of bees. They all looked alike except as to size. They were green with scales, and they had four legs and a long tail and great wings like bats' wings, only the wings were a pale, half-transparent yellow, like the gear-boxes on bicycles.
Based on the rising action in the bolded paragraphs, what do we know about Daddy? (5 points)
He is calm and curious.
He is angry and upset.
He is hysterical.
He is uninterested and bored.
Answers
believe in fairy stories. At first there were only a few, but in a week or two the country was simply running alive with dragons of all sizes, and in the air you could sometimes see them as thick as a swarm of bees. They all looked alike except as to size. They were green with scales, and they had four legs and a long tail.
Explanation:
YOUR WELCOME :)
Answer:
its "calm and curious"
Explanation:
hope tis helps!!!
Nuclear power stations convert the nuclear energy stored in nuclear fuel into what other store of useful energy?
Answers
Answer:
The right answer is "thermal energy" or "thermal" or "heat" or "heat energy" or "electricity" or "electrical energy"
Explanation:
Nuclear fuel is used to heat water, increasing its thermal energy. This hot water is used to turn turbines that generate electrical energy.
Nuclear power stations convert the nuclear energy stored in nuclear fuel into thermal energy.
What is thermal energy?
Thermal energy is defined as a type of energy which is contained within a system which is responsible for temperature rise.Heat is a type of thermal energy.It is concerned with the first law of thermodynamics.
Thermal energy arises from friction and drag.It includes the internal energy or enthalpy of a body of matter and radiation.It is related to internal energy and heat .It arises when a substance whose molecules or atoms are vibrating faster.
These vibrating molecules and atoms collide and as a result of which heat is generated in a substance , more the collision of particles , higher is the thermal energy.It has 3 types conduction, convection and radiation.
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