Kinetic energy Definition and 1000 Threads

Homework Statement A body is moving on a horizontal plane which gradually turns to another plane forming an angle ##α##. Friction coefficient is ##μ##. Find the kinetic energy of the body after the turn if in the beginning it was ##K_o##. Homework Equations Newton's laws. The Attempt at a...

Homework Statement Homework Equations Please see below. The Attempt at a Solution I'm pretty sure my method is correct but I'm getting small answers: $$ COM \\ \\ E_{6}= E_{2}+E_{\alpha} \\ \\ Minus \ E_{2} \ and \ square \ both\ sides\\ \\ E_{6}^{2}+E_{2}^{2}-2E_{2}E_{6}=E_{\alpha}^{2}\\...

Homework Statement Hi,I have been struggling on this problem for a whole day,looking for someone to sort it out! My question:(please see the attached diagram as well) Consider 2 spheres A and B,having different masses (m and M) but equal in size. A is moving to the right at a speed u, B is...

Homework Statement So first the task: Determine the average value of the kinetic energy of the particles of an ideal gas at 0.0 C and at 100 C (b) What is the kinetic energy per mole of an Ideal gas at these temperatures. I took the above right out of the pdf we got from our professor. I know...

Homework Statement A truck is moving at constant velocity v0 with a box of mass m on it. Suddenly it starts decelerating until its velocity becomes zero. Between the box and the truck the is a force of friction and the deceleration of the truck is sufficiently slow to allow the box not to start...

I am having trouble deciding when to use which equation. If you're given the wavelength of a proton, let's say 100 fm, and have to find the kinetic energy of it, how would you do this? Here are my ideas: Idea 1: Use lambda = h/p, where p = sqrt(2Em). Idea 2: Use E=(pc)^2+(mc^2)^2 =...

Homework Statement Homework Equations Q = c m ΔT The Attempt at a Solution so converting 55 mph to meters per sec gives me a velocity of 24.58 m/s kinetic energy of car is 1/2 m v2 i set 1/2 m v2 = c m ΔT plugging in v and c and masses of both ΔT = 134.56 is that correct?

Homework Statement A bullet of mass 2.0 * 10-3 kg is fired horizontally into a free-standing block of wood of mass 4.98 * 10-1 kg, which it knocks forward with an initial speed of 1.2 m s-1. (a) Estimate the speed of the bullet. (b) How much kinetic energy is lost in the impact? (c) What...

Homework Statement The problem is that my teacher asked to solve this using kinetic energy but i doubt it uses kinetic energy... i thought it uses potential energy. [/B] You put your little sister (mass m) on a swing whose chains have length L and pull slowly back until the swing makes an...

Homework Statement The kinetic energy (in keV) of the alpha particle, when the nucleus 84210Po at rest undergoes alpha decay, is A 5319 B 5422 C 5707 D 5818 Homework Equations ## E = mc^2 ## Kinetic energy ## = mv^2/2 ## The Attempt at a Solution alpha particle is emission of helium nucleus...

Homework Statement After being hit, a 0.145 kg baseball has a speed of 45.6 m/s. 1. What is the kinetic energy of the baseball after it has been hit? 2. How much work is done on the baseball by the baseball bat? 3. In moving through the air, the baseball slows down to a speed of 30.0 m/s...

Homework Statement A particle charge of 7.6μC is in a uniform electric field directred to the left. Another force, in addition to the electric force, acts on the particle so that when it is released from rest it moves to the right. After it has moved 8cm, the additional force has done...

As we know that every object that has kinetic energy could also have potential energy. Now suppose an object is in rest at a distance of h meter from ground so it has some potential energy and no kinetic energy, now if it starts to fall towards the ground can we say that its total potential...

I am curious about how a particle's kinetic energy changes with the explansion of the unverse. I calculated that for a matter dominated universe it would vary as 1/a2, while the photon temperature varies as 1/a. Is this correct? Is this also true in general? If so, the implication would be...

In case of quantum LHO in eigen state of the system ##|n \rangle## \langle \hat{T} \rangle=\langle \hat{U} \rangle=\frac{1}{2}(n+\frac{1}{2})\hbar \omega What will happened in some superposition of states? Does Ehrenfest theorem can tell me something more general? Is it possible to say that...

I was wondering why the average kinetic energy is calculated in this manner. They are dividing the kinetic energy function by the period (noted here as To) and integrating it with limits from 0→To. Why? (This is a tiny portion of a larger textbook example, not an actual assignment.) Sorry for...

Since kinetic energy is in is a scalar quantity in joules, then is the v in (1/2)mv2 speed or velocity?

Hi, here i need to calculate the tilt angle of the scissor lift. I had done some reviews for designing a scissor lifter, some source state that, tip-over will happen only when the kinetic energy of the system is less than the Potential energy after impact. Hence, i was trying to use this...

I have performed an experiment testing how mechanical energy is conserved. I conducted this experiment by first creating a ramp. I gathered data by first calculating the gravitational potential energy of a marble on various points on the ramp (depending on height). Next I rolled the ball down...

Has anyone ever seen KE derived this way? The only non-classical assumption is that mass = Energy/c^2 (I know, that's a big one) and that it accumulates as mass as the object is accelerated. (sorry for the plain text formatting, I need to learn how to do it right, I may reply with my first try)...

1. The temperature of air wil ... if we add a hydrogen molecule of a speed higher than 1980 m s/-1. 2. The temperature of air will ... if we take away a hydrogen molecule of a speed highr than 1980 m s /-1. 3. The temperature of air will ... if we take away a hydrogen molecule of a speed lower...

Imagine this object as a big tanker ship, moving to the right weight 500 000 metric tones linear velocity 0.01 m/s momentum cca 5 000 000 kg m/s kinetic energy 25 000 J, which is 25 kilowatt-secondshow much power could i extract from this object in order to slow it down to complete stop ...

Lets think we have a sphere and it moves a constant veloctity v.So it will have a kinetic energy.Is this kinetic energy efectts spheres particle energy.(sphere made up but atoms) Thanks

Hi fellow scientists and engineers, I have a question regarding the design of a flywheel. I know that the actual engineering of a flywheel is very complex and in no way I should expect actual practical answers from this simple question. I'm just trying to get some estimates for a renewable...

What equations can be used to compare the force of a resting X mass to the force of a smaller Y mass falling Z distance. Specifically, how much resting mass would equal the force of 300 pounds being dropped from 10 feet up?

Homework Statement There is a system consists of a ball and the earth. Explain why you can consider the kinetic energy of the system equals to the kinetic energy of the ball. Homework Equations ##F=-\frac{m_{1}m_{2}}{{r}^{2}}## The Attempt at a Solution The magnitude of the force acting on...

Why is the average kinetic energy of the molecules a cold liquid less? As the temperature of a liquid decreases, the average kinetic energy of its molecules reduce. What is the reason behind this?

Homework Statement If I have a ball moving in a circular path (ball is connected to a string), as shown in this picture: http://w3.shorecrest.org/~Lisa_Peck/Physics/syllabus/mechanics/circularmotion/Images/cent_force_on_ball.gif should I say that the energy of the ball is both its kinetic...

Homework Statement A car has a power output of 45kW and travels at a constant speed of 30m/s. What force is the engine applying on the car? Homework Equations F=m*a W=ΔKE+ΔGPE KE=½mv^2 GPE=mgh W=F*d P=ΔE/ΔT gh_1+½v_1^2=gh_2+½v_2^2 The Attempt at a Solution I really have no clue. Since there...

Homework Statement Find the speed parameter β and Lorentz factor γ for an electron that has a kinetic energy of: a) 6.00 keV b) 2.00 MeV c) 4.00 GeV Homework Equations KE=(γ-1)*511 KeV SQRT(1/(1-β^2))=γ The Attempt at a Solution a) 6 KeV=(y-1)*511 y=1.0117 1.0117=SQRT(1/(1-β^2)) β=0.152 b)...

Hi, I'm just an average guy here, mostly self educated, and am looking for experts to verify my theories on developing revolutionary impact protection. If I disrupt direct impact to the head using a highly elastic layer of material, does that create an inelastic impact interruption? A helmet...

In the included picture, I don't get how they get to the kinetic energy part. I would say, that the traveled distance is equal to (l + x(t))*θ. Then I would take the time derivative, resulting in dx(t)/dt * θ + (l + x(t))* dθ/dt. Then I would square this result and multiply that with 1/2 m. But...

Hello! I've read that electrons can only absorb photons of exactly the right amount of energy to move to a higher energy level, if its to little or too much then it doesn't absorb it at all, so my question: How can electrons be liberated from an atom with Kinetic energy when they can't absorb...

The question is about 2 sticks standing above each other, but i have a more general question. The position of my mass is described by: (2rsin(a) - rsin(b) , 2rcos(a)+rcos(b)) the goal is to get a formula for the kinetic energy, so i need the speed of the mass. If i take the derivatives of...

Kinetic Energy of Double Compound Pendulum and Parallel Axis Theorem Hello, there. I have a project I'm working on where I need to be able to calculate the kinetic energy of what basically amounts a double compound pendulum. However, the pivot point of the second pendulum is not at the center...

I think its correct to state that: "Kinetic energy is a property of a moving object." But would it be correct to state that: "Kinetic energy is carried by a moving object"? If not is there a better alternative terminology to use? Thank you.

Homework Statement I was given a chart to figure out the different momentum and kinetic energies of different collisions (elastic and inelastic) and in the lab he posed the question "Calculate the percent elasticity for each of the collisions." Homework Equations conservation of momentum...

The question is. There are two particles, one with charge -q and the other with charge Q, and -q particle rotates around the Q particle at a radius r1. What is the Energy at this point? The answer is like this: E= KE + U So now I know that U= -kQq/r1 But according to the answer: KE= kQq/2r1...

Homework Statement A 6.0-kg object, initially at rest in free space, “explodes” into three segments of equal mass. Two of these segments are observed to be moving with equal speeds of 20 m/s with an angle of 60° between their directions of motion. How much kinetic energy is released in this...

Homework Statement A pion at rest (mπ = 273me) decays into a muon (mμ = 207me) and an antineutrino (mn ≈ 0). Find (a) the kinetic energy of the muon and (b) the energy of the antineutrino in electron volts. Homework Equations K = (γ-1)mc2 E = γmc2 ER = mc2 E2 = p2c2 + (mc2)2 I didn't...

Homework Statement [/B] Objects A and B, of mass M and 2M respectively, are each pushed a distance d straight up an inclined plane by a force F parallel to the plane. The coefficient of kinetic friction between each mass and the plane has the same value...

Question: A streetcar is freely coasting (no friction) around a large circular track. It is then switched to a small circular track. When coasting on the smaller circle its speed is: a) greater b) less c) unchanged Relevant Formulas: w = v/r KE = 1/2mv2 My teacher said the normal force from...

If an object is dropped from height, h, then gravitational energy is E = mgh, but kinetic energy when object hits the ground is E=(1/2)mv^2. Conservation of energy states that E(g)=E(k). Why does kinetic energy not depend on height object was dropped?

Homework Statement Homework Equations 1/2 mv^2 = mgh The Attempt at a Solution first, a side question, if p = mv, can't we just place p into 1/2 mv^2 so it becomes 1/2 p^2? anyway, on to the question, at the point where the cube falls off, the Fnormal should just about equal 0, correct? is...

Homework Statement Prove kinetic energy is relationship between mass and velocity using E(g)=mgh (no calculus, momentum, kinematics). Homework Equations gravitational energy: E=mgh kinetic energy: E=(1/2)mv^2 The Attempt at a Solution I know it can be derived using the gravitational energy...

Homework Statement A crate of mass 9.2 kg is pulled up a rough incline with an initial speed of 1.52 m/s. The pulling force is 110 N parallel to the incline, which makes an angle of 20.6° with the horizontal. The coefficient of kinetic friction is 0.400, and the crate is pulled 4.94 m. (e)...

Homework Statement So the first part asks to prove the time derivative of kinetic energy is dT/dt=F dot product v which I did not problem. but then the second part of the problem asks to prove that if the mass is changing with time then the time derivative of d(mT)/dt=F dot product m and I'm...

In class we had a conceptual problem: There will be a race between two springs. Both will receive the same initial impulse, but one has been agitated and is therefore oscillating in some way, the other is just still. Who arrives first? The answer is that the still spring arrives first because...

Homework Statement Imagine that you have been given the job of desiging a new bungee jumping platform. Customers of mass 53.0 kg will step off a platform, attached to a rope of unstretched length 52.6 m and spring constant 17.0 n/m. How far below the platform will the end of end of the rope...

Hi all, Does electromagnetic radiation actually carry kinetic energy? Looking around the web gives different answers. I have seen explanations like radiation pressure experiments as evidence, but this has been argued being effects from energy absorbed by the recipient. In case it does not...