Kinetic energy Definition and 1000 Threads

When I learned about operators, I learned <x> = ∫ Ψ* x Ψ dx, <p> = ∫ Ψ* (ħ/i ∂/∂x) Ψ dx. The book then told me the kinetic energy operator T = p2/2m = -ħ2/2m (∂2/∂x2) I am just think that why isn't it -ħ2/2m (∂/∂x)2 Put in other words, why isn't it the square of the derivative, but...

1. Problem Statement: A worker lifts a heavy crate vertically 1.0 m in 2.0 s. If she lifts the same crate the same distance in 1.0 s, the work was done by her is A the same. B two times as great. C half as great. D four times as great. E one-fourth as great...

Homework Statement I really don't have a homework question just a thought. Is rest energy "maximum energy" for a particle? As to say a particle at rest has a given energy, so when it is in motion it transfers some mass energy to kinetic energy, where both the mass and kinetic energy together...

Homework Statement When gas is burned in a cylinder of an engine it creates a high pressure that pushes a piston. If the pressure is 100psi and it moves a 3 inch in diameter piston a distance of 5cm every .1 seconds. How much horsepower does this action produce?Homework Equations Pressure =...

Homework Statement "In Fig. 8-33, a runaway truck with failed brakes is moving downgrade at ##130\frac{km}{h}## just before the driver steers the truck up a friction-less emergency escape ramp with an inclination of ##θ=15°##. The truck's mass is ##1.2⋅10^4kg##. What minimum length L must the...

Homework Statement An 8.0-kg object is sliding across the ice at 2.34 m/s in the positive x direction. An internal explosion occurs, splitting the object into two equal chunks and adding 16 J of kinetic energy to system. The explosive separation takes place over a 0.16-s time interval. Assume...

Homework Statement If a ball is dropped from a height (H) its velocity will increase until it hits the ground (assuming that aerodynamic drag due to the air is negligible). During its fall, its initial potential energy is converted into kinetic energy. If the ball is dropped from a height of...

Homework Statement Show that the largest possible change in the kinetic energy , ##\Delta E_{kin}##, of a particle of mass ##m## running into another particle of mass ##M## at rest in the lab coordinate system is \Delta E_{kin} = \frac{-4AE_{kin}}{(1+A)^{2}}, where ##A = \frac{M}{m}##...

Homework Statement What potential difference is needed to give a helium nucleus (Q = 3.2 × 10-19 C) 50 keV of kinetic energy? Homework Equations V=U/Q 3.2 × 10-19 C = 2e The Attempt at a Solution I was quite sure I had the right answer but it keeps saying I'm wrong? V = (50*10^3 eV) / 2e =...

Hey guys, this question has boggled my mind not because I don't know how to approach it but apparently the method I'm using is incorrect! Question A cannonball with a mass of 150 kg is fired from a cannon. The cannonball leaves the cannon with 447.9 kJ of kinetic energy. The cannon makes an...

Hello everyone, currently working on a physics project. I was very curios about waterwheels and actually have an overshot waterwheel setup. I was testing how the efficiency of a waterwheel would be effected by the drop height of water onto the waterwheel. Do any of you have any idea how I can...

Homework Statement If the speed of a vehicle increases by 2m/s then it's kinetic energy is doubled. Find out the original speed of the vehicle Homework Equations 1/2(mv^2) The Attempt at a Solution First find out both KE(kinetic energy) taking u(initial vel.) And v(final vel.) And mass as m...

In an inelastic collision is the change in kinetic energy equal to the difference of final and initial momentum if one of the objects is initially at rest? For example: m1v = (m1+m2)Vf -----> 0 = (m1+m2)Vf - m1v1 1/2(m1+m2)Vf^2 - 1/2m1v^2 = (m1+m2)Vf - m1v1 Or totally wrong? Thanks!

If a car crashes with a stationary tree and comes to stop, we could say that the kinetic energy of the car was converted to heat and that the collision was inelastic. However, conservation of momentum dictates that momentum is still conserved. How would that be possible given that neither the...

KE is proportional to v^2. In a gravitational field KE=1/2 m*v^2. It's easy to find mathematically Work=Fd=mad=m(v/t)(v*t)=m*v^2. But how to visualize it or get an intuitively "feel" for this v^2 relationship?

A spring of spring constant k sits on a frictionless horizontal table, one end of the spring is attached to a wall the other end to a block of mass M= 2kg, also resting on the frictionless table. Another block of mass m=450g moving at a speed of 7m/s collides in-elastically with the block of...

Homework Statement The question is: A 2 kg particle is moving in the positive x direction with the speed of 5 m/s. As it passes the origin, a force F = (30 N - 2N/s*t)i is applied to it. Where does the particle come to a stop? Homework Equations F=ma W = integral F(x)dx K=.5mv^2 The Attempt...

1.e problem statement, all variables and given/known data Two positrons and two protons are kept on the four corners of a square of side a. Positrons are kept at vertices A and C and protons are kept at B and D. let q denote the charge on both positron as well as the proton. So what is the...

A 6.0kg metal ball moving at 4.0m/s hits a 6.0kg clay ball at rest and sticks to it. The two move at 2.0m/s. a. calculate the kinetic energy of the metal ball before it hits the clay ball. b. calculate the kinetic energy of the metal ball after it hits the clay ball. c. calculate the kinetic...

Homework Statement Given, force of constant magnitude, which is always perpendicular to the velocity of the particle & the motion takes place in a plane. What happens to its kinetic energy? Explain. Homework Equations Work energy theorem The Attempt at a Solution According to work energy...

Homework Statement A resting electron was sped up to 0.5 of the speed of light. Find: A. relativistic mass of the electron, B. total energy of the electron, C. kinetic energy of the electron. Homework Equations K = mv^2/2 E=mc^2 The Attempt at a Solution Let’s first find the kinetic energy...

Homework Statement Calculate the kinetic energy of CO, CO2, and SO3 at 276 K . Homework Equations KE = (3/2) RT KE= (1/2)(mass)(velocity)^2 The Attempt at a Solution [/B] For CO: First attempt: KE=(3/2)(RT)=(3/2)(8.314 J/mol-K)(276K) = 3441.996 -- So that's wrong Second attempt: Relative...

Homework Statement I have a table that needs to be filled out. In each column, potential and kinetic energy are given, but height and velocity are left blank. Ex: PE = 20 J, KE = 0 J, h = ?, V = ? Homework Equations KE = 1/2mv^2 U = mgh The Attempt at a Solution I'm totally stumped. How can I...

Homework Statement Hi I know my picture has 2 problems, but let's just focus on the first problem parts a and b. So for part a it ask for the final frequency after the ant landed, and part b is the kinetic energy difference. Basically the ant=.01kg, diameter of cylinder is .115m, the weight of...

Homework Statement Why is there more heat and sound energy produced with a larger collision? Homework EquationsThe Attempt at a Solution Honestly no clue. I would really appreciate any help! Any videos would also help!

Hi there, I have a problem to solve in Cosmology which says: "Write the formulas for the quantum kinetic energy of neutrons, protons and electrons as well as the formula for the gravitational energy for a neutron star that is comprised of free neutrons, protons and electrons in a ratio of Nn ...

Is there a threshold of maximum kinetic energy lost when kinetic energy is transferred between two objects through collision? I just cannot find any information on this, any help would be VERY much appreciated.

If i compress water to 60 ksi, and push it through a 0.015" sharp orifice, then i have another orifice 2 feet before that sudden open to 0.015", what is the velocity of the stream from each orifice?

Homework Statement Ok I have the answers to parts a and b, which I am 100% confident in since they are simple computations Question is in attachement a)74.9 rad/s b)168.08 rad My issue comes in when I have to get parts c The mass of the cylinder is 8.7kg, its diameter is .18m, its .35m long...

Homework Statement A 0.26-kg block on a horizontal frictionless surface is attached to an ideal massless spring whose spring constant is 190 N/m. The block is pulled from its equilibrium position at x = 0.00 m to a displacement x = +0.080 m and is released from rest. The block then executes...

Homework Statement Homework Equations i) F=ma=mv/t ii) E=mv2/2 The Attempt at a Solution Now based on equation 1 , I have concluded that the velocity gained is inversely proportional to m, and that so is the kinetic energy , I have seen otherwise.[/B]

My question is: Does a spring between two differing masses, each with an initial momentum of zero, transfer half of its stored elastic potential energy to each? My intuition says yes. But it seems to not be the case. If you apply the conservation of energy and momentum, the answer you get is...

why's there unequal distribution of kinetic energy in water molecules?

Homework Statement The longest homerun hit by Miguel Cabrera in the 2012 season occurred at Comerica Park and had an initial y-component of velocity of 19.8 m/s and an initial x-component of velocity given as m/s, where is some value left undetermined. Assume the ball left the bat 1.22 m off...

Consider the internal energy of a gas and solid (different materials) both at the same temperature, which material has the larger potential energy and why? Do they also both have the same kinetic energy? Finally is the definition of temperature as the average kinetic energy of the particles only...

Homework Statement Two identical twins, A & B, are riding identical bikes up the same hill, both at constant speed. Twin A takes 20 seconds to climb the hill, while twin B takes 40 seconds. a) Neglecting all forms of friction, which twin consumes more energy? b) With friction, which twin...

Stefan throws a baseball with the speed of 140 km/ℎ. The ball goes obviously in goal, but it bounces back out of the net with a speed of 50 km/ℎ. What percentage of the kinetic energy remaining after contact with the net?

my name is Kofi and I am here to learn and understand physics

A block of mass 9kg is initially at rest at the top of an inclined plane of ramp length 4m. -Assuming that the plane is frictionless, calculate the speed of the block at the bottom of the plane. -Now instead assume the a frictionless force of Ffr = 2 Newtons opposes the motion of the block...

In chromatography, the upper portion of the moving water solvent has more kinetic energy, than the lower portion of the moving water solvent because the lower portion of water molecules have to face more obstacles in the way because of the absorbed water molecules. Is it true?

According to special relativity, KE= ([PLAIN]https://upload.wikimedia.org/math/3/3/4/334de1ea38b615839e4ee6b65ee1b103.png-1)(mv^2)/2. Since the velocity measured is dependent on a person's frame of reference, then does that mean energy too is dependent on frame of reference? For example, if an...

Hi Guys,When we are finding the wasted energy when something is dropped a tower, we do this: mgH-0.5mv^2 My question is, does the velocity of the kinetic energy have to be vertical component, or can it be the impact velocity when it hits the ground? Thanks

Homework Statement A large wooden turntable in the shape of a flat disk has a radius of 1.50 m and a total mass of 100 kg. The turntable is initially rotating about its vertical axis through its centre with an angular velocity of 2.50 rad/s. From a very small height a 100 kg sand bag is...

Homework Statement A rollercoaster has a loop with a radius of 12m. The coaster travels 50m and at point A, enters the loop. The average frictional force on the coaster is 40N. The mass of passenger is 50kg. What is the minimum kinetic energy required at point A to generate a velocity of 27m/s...

Homework Statement An object moves in uniform circular motion. Its kinetic energy is directly proportional to: I. centripetal force II. radius of the circle III. the period of circular motion Homework Equations I took the universal gravitational law G* m1 * m2 /r^2 = m2 * v^2/r and then I...

Usually when we calculate the kinetic energy acquired by a positive charge as it moves in the direction of the electric field produced by another positive charge, we assume that the source charge remains stationary and so the loss in potential energy for the moving charge is equal to its gain in...

Given the relativistic equation for energy E2 = (pc)2 + (mc2)2 I want to find the non-relativistic approximation for kinetic energy in non-relativistic terms, Knr = p2/2m I start off with subtracting the rest energy E0=mc2 from the above equation. So K = E - E0 and assume that c is very...

Homework Statement A ball rolls down an incline plane without slipping. What is the ratio of its angular velocity at h/3 to its angular velocity at 2h/3? 1) 1:2 2) 1:sqrt(2) 3) 1:1 4) sqrt(2):1 5) 2:1 Homework Equations Conservation of energy with provisions for rotational and...

Homework Statement What is the moment of inertia of a spinning object of radius 0.5 m and mass 6 kg moving at 5 m/s, if it has a kinetic energy of 100 J? 1) 1 kgm22) 2 kgm23) 4 kgm24) 8 kgm25) 20 kgm2 Homework Equations K.E. = Kinetic energy of rotation + kinetic energy of...

Homework Statement An object is in freefall on Earth. Which of the following statements is true? A) The object is gaining an equal amount of momentum for each second it is in free fall.B) The object is gaining an equal amount of momentum for each meter it falls.C) The object is gaining...