Kinetic Definition and 1000 Threads

  1. D

    Kinetic Theory - Mass on a piston

    Homework Statement A cylinder containing an ideal gas is in vertical position and has a piston of mass ##M## that is able to move up or down without friction (Fig. 13.2). If the temperature is increases, ...Fig (13.2) (a) both ##p## and ##V## of the gas will change. (b) only ##p## will...
  2. O

    B Rest Energy - Kinetic Energy

    We are giving a particle with mass 400 Mev/C2 and 200 MeV KE. What is the Energy of the particle? Is it 600 MeV or 200 MeV?
  3. Z

    What is the Relationship Between Kinetic Energy and Momentum?

    Homework Statement Homework Equations K.E = p^2/m The Attempt at a Solution [/B]
  4. Low-Q

    Force, mass, acceleration, kinetic energy

    Hi all, I stumbled into a somewhat odd mathematical problem, so I guess I've overlooked an important detail. If I have a mass of 1kg on wheels horizontally, and apply 10N of constant force so the mass is accellerating. I assume the velocity of that mass after 1 second is approx 10m/s. Then...
  5. S

    Calculating Forces and Kinetic Friction for a System of Connected Blocks

    Hi everyone, I'm having a difficult time figuring out this problem. Could someone give me some pointers? I set up the equations and the free body diagrams (hopefully they're correct) ; all I have to do now is solve for F.1. Homework Statement A block of mass m is on top of a block of mass M =...
  6. BitWiz

    Kinetic energy: Legal to use kinetically independent frames?

    A rocket is drifting in gravity-free space and is observed by an external observer who is also drifting at an unchanging location using an arbitrary coordinate system. The rocket accelerates at a fixed rate using a massless photon engine that results in a negligible change in the mass of the...
  7. Cocoleia

    DeBroglie wavelength based on kinetic energy

    Homework Statement I am working on a problem similar to this one: In this solution, I do not understand what mc is, can someone explain? Also, would I follow the same type of steps if I have the kinetic energy of a photon and I need it's wavelength? Homework EquationsThe Attempt at a Solution
  8. J

    Understanding Work and Kinetic Energy: Examples and Calculations Explained

    I am confused of how Work basically equals to Kinetic Energy...I will give an example just as way to help you help me get an idea about how it works...the example I thought of is... '' James (100 kg) jogs on a straight road at a constant velocity of 2.2 m/s for 600 seconds, how much energy does...
  9. M

    Work done on brakes vs kinetic energy lost by vehicle

    When doing work on the brakes of a car or bicycle, how much of that energy is actually removed from the total kinetic energy of the vehicle? What is the most efficient braking system?
  10. I

    Does light contain kinetic energy?

    Does light contain kinetic energy as it moves, or does it require mass.
  11. V

    Should I consider Linear Kinetic Energy in this Equation

    Sorry If the thread name confuse you. I want to know if I want to find the Torque from deriving Kinetic Energy and the system has Object the Rotate and the rotating cause linear motion(v). Let's say it a Rolling Disc on the non-slope plane which has angular velocity ω and that ω cause it to move...
  12. Konte

    I Internal rotation kinetic energy operator

    Hello everybody, My question today is: Given a molecule that has an internal degree of liberty ( let's take the ethane molecule with its internal rotation as an example), how to write the kinetic energy operator by means of the corresponding internal coordinate? Thank you guys. Konte
  13. A

    I How Do You Calculate the Average Orbital Kinetic Energy for Silicon?

    Hi! I search the way to calculate the average orbital kinetic energy like is given in :http://physics.nist.gov/cgi-bin/Ionization/bun.php?Id=AlI (here is for aluminum). I would like use the underlying method to calculate the average orbital kinetic energy for the silicon (Si) element. If you...
  14. Cocoleia

    Relativistic kinetic energy and momentum

    Homework Statement A proton has a speed of 0.2c. Find the speed of an electron that has (a) the same kinetic energy as the proton, and (b) the same momentum as the proton. Homework Equations K=ϒmc^2-mc^2 The Attempt at a Solution This is what I did for the same kinetic energy part, but I...
  15. S

    Calculate the Kinetic Frictional Force

    The alarm at a fire station rings and a 71.3-kg fireman, starting from rest, slides down a pole to the floor below (a distance of 3.63 m). Just before landing, his speed is 1.42 m/s. What is the magnitude of the kinetic frictional force exerted on the fireman as he slides down the pole? Givens...
  16. K Wils

    Average Coefficient of Kinetic Friction between Ice and Puck

    1. The problem: A hockey puck is hit on a frozen lake and starts moving with a speed of 11.6 m/s. Five seconds later, its speed is 7.4 m/s. What is its average acceleration? The acceleration of gravity is 9.8 m/s. Answer in units of m/s. What is the average value of the coefficient of kinetic...
  17. nickyfernandezzz

    Kinetic energy to thermal energy

    Hey guys, I need help with the following question. A lead ball of specific heat capacity 130J/KgK travels with a speed of 100m/s before it hits a wooden cube fixed to floor and gets stuck inside.What will be the rise in temperature of this lead ball by the time it comes to I attempted the...
  18. P

    How to find Coeff of kinetic friction without mass?

    Homework Statement For my Physics lab this is what my teacher handed me... I have no idea how to attack the situation, can someone help solve? Devise a procedure for an experiment which will measure the coefficient of kinetic friction between a block of unknown mass m and the table, where the...
  19. H

    Mechanics - Work and Kinetic Energy, (Spring on a Ramp)

    Hi everyone, I've been systematically working through the exercises in my first year college textbook and have come up confused over this particular problem. I have a solution manual but it solves this problem differently than I did, though comes up with a similar answer. I've included my...
  20. cheapstrike

    What are the effects of impulse and kinetic energy on two identical spheres?

    Homework Statement Two identical spheres A and B are kept on a smooth surface. They are given the same impulse I. The lines of action of impulses pass through the center of A and away from the center of B. Then: (A) linear kinetic energy of B will be less than that of A. (B) B will have...
  21. Q

    Reverse engineering potential and kinetic energy

    The equation for momentum (potential energy) is PE=M*V. The equation for kinetic energy is KE=(1/2)*(M*V^2). You will notice that PE is the derivative of KE. and then you might add that M, simply Mass, is the derivative of PE. However, because M is simply a scalar quantity, and the other...
  22. F

    How much kinetic energy do I need to impart?

    Homework Statement I'm actually making up my own problem here to try to resolve some confusion I'm running into on understanding kinetic energy and reference frames... Let's launch a potato of mass m (just call it 1) horizontally with a potato gun on a fast vehicle moving 50 m/s, while I'm...
  23. T

    Lower kinetic temperature implies population inversion?

    I was just wondering: why does lower kinetic temperature imply population inversion? I've read this is true in a few (astrophysics) texts regarding molecular clouds, although this seems to be a more general result that I haven't really read an entire explanation for. Nevertheless, do you have...
  24. N

    Find coefficient of kinetic friction of block and ramp.

    Homework Statement A small block is on the point of slipping down a rough ramp inclined at 35 degrees to the horizontal. a) What is the coefficient of static friction between the block and the ramp? Answer μ_s = 0.70 b) The ramp is attached to the edge of a 0.8 m high table. After the block is...
  25. K

    Work Kinetic energy using variable force

    Homework Statement The position of an object of mass 2 kg is changing as a function of time by the formula x(t) = 4t^3-6t. (a) find the work done by the forces acting on the particle between t=1 and t=3s. (b) What is the object's velocity when the force on it is zero? Homework Equations is...
  26. Muhammad asad

    Is Kinetic Energy Really Constant in Constant Velocity Motion?

    I am really confused here. I have studied that if the kinetic energy of a moving body is not changing then the net work being done on the object is equal to zero. But when we are talking about a body moving upwards at constant velocity there is no change in its kinetic energy but there is still...
  27. Hallucinogen

    Is the normal force just kinetic energy?

    I'm confused; forgive me if this dumb. I'm trying to reason what "force" is, on a molecular level. I'm only concerned about normal forces here (pushes and pulls), not field forces. Forces in Newtons are vector quantities and only represent relationships between two things right? It isn't...
  28. Her0

    Finding the force of kinetic friction without a coefficient

    Homework Statement In a lab assignment we created a Fletcher's trolley system and were asked to calculate the normal force, the force of friction, and then create a graph of both to find the coefficient of kinetic friction. So far, the variables I have are: Hanging mass: 0.100 kg Sliding...
  29. Konte

    I Will the kinetic energy operator change with a variable shift?

    Hello everybody, A special problem constrain me to make a variable change in my Hamiltonian operator, so with the kinetic energy operator, I have a doubt. The variable change is: ## \theta \longrightarrow (\theta + k) ## (where ##k## is a constant). And the kinetic energy operator...
  30. ChloeYip

    Gas Kinetic Energy: Monatomic or All Gases?

    "KE=3/2nRT=3/2kT" is applicable to only monatomic gas or all kind of gas? What about " KE=1/2*fkT" ? (f: degree of freedom) Is it implies the same thing as "KE=3/2nRT=3/2kT" ? Thank you.
  31. H

    Kinetic energy change with initial velocity

    It is my understanding that to calculate the change of kinetic energy of an object that speeds up from vi to vf you use this formula: Change of kinetic energy = 1/2 * m * (vf2 - vi2) When the initial velocity is 0 m/s I have no problems, but let's say an object that weighs 2 kg speeds up from...
  32. Mister T

    Kinetic Energy and Momentum of a Relativistic Particle

    College-level introductory physics textbooks usually devote a chapter to special relativity. Peter J. Riggs in his article appearing in the February 2016 issue of The Physics Teacher (pp 80-82) derives a couple of expressions for the kinetic energy of a massive (as opposed to massless) particle...
  33. R

    How Long Does It Take for the Block to Reach the Other Side?

    Homework Statement A small block of mass 1.74 kg rests on the left edge of a block of length 3.05 m and mass 7.95 kg. The coefficient of kinetic friction between the two blocks is 0.279, and the surface on which the 7.95 kg block rests is frictionless. A constant horizontal force of magnitude...
  34. K

    B Question about Hamiltonian and kinetic energy

    basically, as far as I know we can derive 1/2mv2 from ∫F⋅ds=1/2mv2=(p2)/2m for wave equation we use Hamiltonian H=P2/2m+V where P and V are both operators However, I wonder how we can say that P2/2m is the term for kinetic energy because ∫F⋅ds=∫(dp/dt)⋅ds=1/2mv2 is saying that knowing F and...
  35. N

    A Fetter & Walecka's derivation of second-quantised kinetic term....

    On page 9 of *Quantum theory of many-particle systems* by Alexander L. Fetter and John Dirk Walecka, during the derivation of the second-quantised kinetic term, there is an equality equation below: >\begin{align} \sum_{k=1}^{N} \sum_{W} & \langle E_k|T|W\rangle C(E_1, ..., E_{k-1}, W...
  36. Cocoleia

    Loss of kinetic energy due to heat

    Homework Statement I have a bloc sitting on a horizontal table, and we shoot a ball through it. The speed right before entering the block is v and the speed when it exits the block is v/2. I need to prove that the fraction of the initial energy that is lost due to heat is 3/4 - γ/4, where γ is...
  37. A

    Find the potential, kinetic, and mechanical energy

    Homework Statement A 1.40 kg block slides with a speed of 0.885 m/s on a frictionless horizontal surface until it encounters a spring with a force constant of 637 N/m . The block comes to rest after compressing the spring 4.15 cm. Part A Find the spring potential energy, U, the kinetic energy...
  38. E

    By how much does your force change the kinetic energy

    Homework Statement You push a blob of gelatin with a constant force of 2.4 F across a wet table on which it slides easily. Because the blob shape distorts, its center of mass moves only 33 mm during the time interval in which the point of application of your force moves 53 mm . By how much does...
  39. E

    What is the kinetic energy of the center of mass

    Homework Statement Two 0.50-kg carts are pushed toward each other from starting positions at either end of a 6.0-m low-friction track. Each cart is pushed with a force of 2.9 N , and that force is exerted for a distance of 1.0 m. What is the kinetic energy of the center of mass of the system...
  40. HenryWhu

    The kinetic energy of the electrons outside the FBZ

    Homework Statement In solid state physics,we know all the states of free electrons can be expressed by the First Brillouin Zone. We know the $$E(k+K)=E(k)$$ where K is reciprocal lattice vector. We also know that the kinetic energy of the electron is $$E_{k}=\frac{\hbar^2k^2}{2m}$$. [/B]...
  41. V

    A doubt from Kinetic Theory of Gases

    I have read Average translation kinetic energy is 1/2RT per degree of freedom and Average translation kinetic energy for an ideal gases is 3/2RT.How? Does it imply f=3 for all ideal gases?
  42. Christofferk

    Kinetic energy of the hydrogen atom in its ground state

    I saw another post about this but i didn't quite find what i was looking for there so i thought i'd give it a go instead with a thread. Homework Statement Calculate the exact value of the kinetic energy of the hydrogen atom in its ground state. No more information is given, we are referred to...
  43. J

    Kinetic energy of a rolling hoop

    Homework Statement A 120 kg hoop rolls along a horizontal floor so that its center of mass has a speed of 0.240 m/s. How much work must be done on the hoop to stop it? Homework Equations I of hoop=MR^2 The Attempt at a Solution KE=0.5*m*v^2+0.5*(mR^2)(v/R)^2...
  44. T

    (2/3) as constant factor In Kinetic theory of gases

    Hi I'm in high school but what I'm going to ask you is probably being teached in college. General formula: p=(2/3)*(N/V)*Ek p- pressure N- amount of molecules V- volume of the container Ek - AVERAGE kinetic energy I've been told by my physics teacher, that 2/3 constant factor in kinetic theory...
  45. J

    What is the Change in Kinetic Energy of a Crate Being Pulled at an Angle?

    Homework Statement A.What is the change in kinetic energy of the crate? Answer in units of J. B.What is the speed of the crate after it is pulled 5.79 m? Answer in units of m/s Magnitude of work done by gravity= 200.786 Work done by applied force= 822.18 mass=8.91kg force pulling on box= 142N...
  46. J

    Kinetic Energy of a Particle in a semi-spherical bowl

    Homework Statement A 410 g particle in a semi-spherical bowl of radius 0.9 m is released from rest at point A at the level of the center of the bowl, and the surface of the bowl is rough. The speed of the particle at B is 2.6 m/s. The acceleration of gravity is 9.8 m/s 2 . What is its kinetic...
  47. S

    Friction Lab? Kinetic Friction?

    Homework Statement Hi, we had a Lab Activity on the Coefficient of Friction, but right now I am really confused and stuck. Since the teacher used an online resource, we are supposed to make two graphs based off the data and it's very unclear and unhelpful. :( I can't seem to find anything at...
  48. K

    Efficient way to convert kinetic energy to heat

    I am trying to find the most efficient way to convert kinetic energy to heat. The first thing I know is friction, however friction cause wearing for long term use. The second is convert to electric energy(dynamo) and then convert to heat using electric coil, however I think that has low...
  49. I

    Fraction of molecules have kinetic energy of 1/2mC^2

    Homework Statement Consider a gas of molecules of mass m at equilibrium at temperature T. Obtain an expression for the fraction of molecules having kinetic energy e = 1/2mC2 in the range e to e + de. This is problem 5.3, page 48 of Vincenti and Kruger's Intro to Physical Gas Dynamics Homework...
  50. Erenjaeger

    Rotational kinetic energy of ice skater

    Homework Statement [/B] An ice skater executes a spin about a vertical axis with her feet on a frictionless ice surface. In each hand she holds a small 5kg mass of which are both 1m from the rotation axis and the angular velocity of the skater is 10rad/s. The skater then moves her arms so that...
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