Kinetic energy Definition and 1000 Threads

I'm currently in High School and we have to create an idea to make the world better. Mine is to use the force of gravity and convert it to energy to power a system that will filter air. This is supposed to be used in developing countries where there are large amounts of biomass and harmful...

Homework Statement A trolley of mass 0.5 kg rolls along a level, frictionless ramp at a velocity of 6.0 m s-1. It collides with a second trolley of mass 1.0 kg which is initially at rest. The first trolley rebounds with a speed of 2.0 m s-1 . a) Stating clearly any principles involved, find...

Homework Statement This problem comes from an intermediate step in the textbook's derivation of relativistic energy. It states that E_k\:=\:\int _0^u\frac{d\left(\gamma mu\right)}{dt}dx then leaves the following intermediate calculation as an exercise to the reader: Show that...

On very small scales, an object's kinetic energy tells you its temperature, and on larger scales, an object's kinetic energy tells you its velocity. Where's the cut off? I mean, velocity is relativistic, but temperature... isn't... is it? Also, black body radiation decreases a body's temperature...

I see that black body radiation slowly depletes a body's thermal energy, which is just another way of saying that black body radiation depletes the kinetic energy of a body's constituent particles. But does black body radiation also cut into the kinetic energy of the body as a whole, such that a...

Can anyone please let me know an example where a body has large mass but low Kinetic Energy? Please provide some reasons for same.

Homework Statement Calculate the deBroglie wavelength of a proton moving at 1/4 the speed of light. How does the kinetic energy of this proton compare to its p^2 /2m? What does p^2 / 2m anyway conceptually (isn't it one of the triangle thingies in the lower version of E=mc^2)? Homework...

The mass of a particle will increase as its velocity increases according to special relativity. This has been confirmed in countless experiments in which particle accelerators accelerate charged particles. What type of experiments have confirmed this for uncharged particles? Thanks in advance.

Let's say there are two masses, attached together by a string, and there's a compressed spring in between them. When the string in between is cut off, the spring unloads, pushing both masses in opposite directions. My thinking: 1. Their momentums will be equal to each other. Their momentum...

Hello 1. Homework Statement In a uniform solid cylinder of radius r, mass m and height h we emptied a cylindrical cavity of radius r/4 tangent and parallel to the symmetrical axis z of the original cylinder. The cylinder is rolling without slipping on a horizontal plane. Find the kinetic energy...

Hi guys, I got one confusion when reading Goldstein's Classical Mechanics (page 20, third edition). After getting the equation, then it says that Note that in a system of Cartesian coordinates the partial derivative of T with respect to qj vanishes. Thus, speaking in the language of...

Homework Statement An object has a mass of 10 lbm. b. Find the change in kinetic energy ft·lbf when its velocity decreases from 50 mph to 15 mph. Homework Equations KE=1/2mv^2 Ke=(ft*lbf) 1MPH=1.4667 ft/s The Attempt at a Solution When calculating this, does it need to be in slugs, lbm, or...

Homework Statement A particle of mass m and initial velocity v0 collides elastically with a particle of unknown mass M coming from the opposite direction as shown in the left-hand sketch on the next page. After the collision, m has velocity v0/2 at right angles to the incident direction, and M...

A given planet has a mass, M = 6.42*10^23 kg, and radius, R = 3.39 * 10^6 m. The gravitational konstant is G = 6.67*10^-11 A spaceship with mass m = 4000 kg is launched from the planets surface. How much energy is needed to send the spaceship to a height h = 100 km above the planets surface?

It's my first post so big thanks in advance :) 1. Homework Statement So the question states "By interpreting <pxΨ|pxΨ> in terms of an integral over x, express <Ekin> in terms of an integral involving |∂Ψ/∂x|. Confirm explicitly that your answer cannot be negative in value." ##The 'px's should...

Homework Statement Determine the maximum kinetic energy of a uniform rod of mass 0.5Kg and length 0.75 that has an angular displacement of 5 degrees. Homework Equations y = rsin (x) where x is the angular displacement The Attempt at a Solution Using conservation of energy ETotal = EMech +...

Homework Statement I am trying to get the hamiltonain operator equality for a rigid rotor. But I don't get it. Please see the red text in the bottom for my direct problem. The rest is just the derivation I used from classical mechanics. Homework Equations By using algebra we obtain: By...

Homework Statement The screen shot I have attached is the original question, I think I'm ok up until the Ne part. My answer just seems like a ridiculous number, I haven't had much experience with this so don't really know what an 'normal' KE for 1kg of gas would be. Homework EquationsThe...

Homework Statement Three blocks of identical mass are placed on a frictionless table as shown. The center block is at rest, whereas the other two blocks are moving directly towards it at identical speeds v. The center block is initially closer to the left block than the right one. All motion...

Homework Statement A man pulls a 15-kg sled containing a 5.0-kg dog along a straight path on a horizontal surface. He exerts a force of 55 N on the sled at an angle of 20.° above the horizontal, as shown in the figure above. The coefficient of friction between the sled and the surface is 0.22...

Homework Statement I need to rearrange the change in kinetic energy equation for mass Homework Equations Change in Kinetic energy = 0.5mv^2-0.5mu^2 The Attempt at a Solution [FONT=Times New Roman]I factorised the right hand side to give: [FONT=Times New Roman]Change in kinetic energy...

Homework Statement hello! so i am trying to figure out how to calculate the resultant velocities and directions(angles/vectors) that two perfectly elastic spheres might travel in if they were to be hit simultaneously by a third sphere at an angle. all the spheres are of equal mass, initial...

I would like to calculate the electron kinetic energy ejected from a cathode as a function of the electric field and pressure without known of the temperature and velocity.

Hi all, I have charged particles (protons) accelerated by an electric field. If I add up all the momentum and find the change in momentum per sec I can find the acceleration of my craft by dp/dt /M = a If I add up all the kinetic energy of the particles and find the KE per sec, I can find the...

Homework Statement A Physics textbook weighing 3 kg needs must be launched into a nearby trash can. The velocity necessary to accomplish this feat is 4 meters per second when unleashed in its flight. Assume no wind resistance. What energy is necessary to accomplish this deed? Homework...

Homework Statement A toy car coasts along the curved track shown. The car has initial speed VA when it is at point A at the top of the track, and the car leaves the track at point B with speed VB at an angle θ above the horizontal. Assume that energy loss due to friction is negligible...

Hello PF. I have a question on a concept of Potential and Kinetic energy. So for this let's take a ramp and a ball at the bottom. If I apply a force on the ball to make it go up the ramp, when it starts to move it will gain kinetic and potential gravitational ( I think ) but what about at the...

Homework Statement A 0.50-kg object is attached to an ideal massless spring of spring constant 20 N/m along a horizontal, frictionless surface. The object oscillates in simple harmonic motion and has a speed of 1.5 m/s at the equilibrium position. (a) What is the amplitude of vibration? (b) At...

Homework Statement Given the force ## \vec{ F }(x) = (-12x + 6) \vec{i} ## ; find kinetic energy ## T## at the point ##x=2## and trajectory of a particle ## \vec{r}(t) ##, given that ## \vec{r}(t=0)=\vec{0}## and ##\dot{\vec{r}}(t=0)=\vec{0}## . 3. The Attempt at a Solution Since...

Homework Statement A 1kg object traveling at 1 m/s collides head-on with a 2 kg object initially at rest. If the collision is completely inelastic, determine a) the velocity of the objects after impact and b) how much kinetic energy was lost during the collision. Homework Equations Part a)...

Homework Statement 2 trucks, one with twice as much mass than the other, are at rest on separate tracks. A man pushes each truck for 5 seconds. If you ignore friction and assume equal force is exerted on both trucks - which truck will have the most kinetic energy afterwards? Homework Equations...

Homework Statement An electron e− and positron e+ moving at the same speed in the Earth reference frame collide head-on and produce a proton p and an antiproton p¯. The electron and positron have the same mass. The proton and antiproton also have the same mass. The mass of the proton is 1836.15...

Homework Statement A hoop has a mass of 200g and a radius of 25cm (ICM = MR2 ). It rolls without sliding along level ground at VCM = 5m/s. What is it's total kinetic energy? Homework Equations K = 1/2Iω2 ICM = MR2 v = rω The Attempt at a Solution The answer is 5J, but I'm getting 2.5J. ICM...

A novelty clock has a 0.0109 kg mass object bouncing on a spring that has a force constant of 1.34 N/m. How many joules of kinetic energy does the object have at its maximum velocity if the object bounces 3.49 cm above and below its equilibrium position?

Homework Statement A) A car moving at 18 m/s is accelerated to 35 m/s. If the change in kinetic energy is 154 kJ, determine the mass of the car. Homework Equations [FONT=Times New Roman]KE = 0.5mv^2 Kinetic energy = change in momentum = mv2-mv1 The Attempt at a Solution [FONT=Times...

Hello, When a fluid is flowing, it has of course a kinetic energy and thus we can define kinetic power equal to ρAv v is the velocity and A is the surface of a solid for example. I have a question (maybe it is a strange one) : When fluid collides with a solid, do all the molecules collide with...

Homework Statement An ice cube is placed on top of an overturned spherical bowl of radius r, as indicated in the figure. If the ice cube slides downward from rest at the top of the bowl, at what angle θdoes it separate from the bowl? In other words, at what angle does the normal force between...

I am thinking about something that is getting me quite confused. To illustrate what is confusing me let's have a cart moving in the horizontal direction on a track without friction, and a motor which adjusts to keep the kart at a constant speed V in the positive direction. Now, it's snowing so...

Homework Statement A ball with a mass of 2.3 kg is thrown into the air. If the ball rises to a maximum height of 15 m before stopping and coming back down, how much kinetic energy did the ball have initially? Homework Equations KE=0.5*mass*velocity^2 The Attempt at a Solution I don't think...

Homework Statement I am writing a lab report and I need to calculate the uncertainty error for Gravitational Potential Energy and Kinetic Energy. The Professor told us that the margin of uncertainty for time is +- 0.025 seconds, margin for height is +- 0.001 meters, margin for mass is +-0.001...

Sorry if this question has already been addressed. I know that, at least for a point mass or a rigid body traveling at constant velocity, in special relativity kinetic energy T is defined as: T = E - Mc2 where E is the body's total energy and M its invariant mass. I have a problem in...

Imagine the flagpole and ball with mass m fall together. Can I here use the formula mg*l*sin(theta)=(1/2)*mv^2 If I can, in what direction will the velocity vector be - is it going to be tangential to the flagpole?

Question number 1; find the angular speed. I imagine a point mass at the very top, it has potential energy mgL, this is converted to kinetic energy 1/2*mv^2. I put them equal to each other and say that v=ωL. This gives me ω=sqrt(2g/L), the answer is supposed to be ω=sqrt(3g/L). Why can't I...

I know,kinetic energy=##\frac{1}{2}####mv^2## But I saw one other equation it is kinetic energy=##\frac{1}{2}####|P.E|## Then I started looking for in which specific condition is it true?Because I know it is not always applicable .But I could not find that particular condition when it is true.So...

Homework Statement Homework EquationsThe Attempt at a Solution [/B] a) I think I just have to work out the potential energy and the maximum kinetic energy would is the same? c) Once I've found the kinetic energy, I'm able to work out velocity. Would the velocity be the maximum speed? c)...

Homework Statement Homework Equations [/B] The Attempt at a Solution a) I'm not sure how to calculate speed without having both distance and time but I believe it will revolve around calculating gravitational potential energy and kinetic energy. bi) I think this is just simply using the...

Homework Statement The 2 kg piece of putty is dropped 2m onto the 18 kg block initially at rest on the two springs, each with a stiffness k =1.2kN/m . Calculate the additional deflection of the springs due to the impact of the putty, which adheres to the block upon contact. Homework Equations...

Hello! :) When solving a problem, I had to calculate the angular velocity of a homogenius rod when it comes to vertical position, after being released from a horisontal position (the rod is fixed at one end). This is as usually done with energy conservation, using the rotational energy of the...

Homework Statement An oxygen atom is 3.00 times as massive as a helium atom. In an experiment, a helium atom and an oxygen atom have the same kinetic energy. What is the ratio VHe/VO? Homework Equations KE = 1/2 mv^2 The Attempt at a Solution I know KE for helium is = 1/2 mv^2 and KE for...

Homework Statement A billiard ball (Ball #1) moving at 5.00 m/s strikes a stationary ball (Ball #2) of the same mass. After the collision, Ball #1 moves at a speed of 4.35 m/s. Find the speed of Ball #2 after the collision. Homework Equations Conservation of Kinetic Energy Conservation of...