Kinetic Definition and 1000 Threads

Homework Statement Pressure in vacuum is 10^-3 Torr. External Pressure is 1atm and 300K. Pinhole of 10^-10cm^2 made in vacuum. Assuming all molecules striking hole pass through, how many molecules leak into vacuum in 1hour? Answer: 10^17 molecules Homework Equations Flux = <v>*N/4V Rate = Flux...

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?

A box weighing 87 lb is being pulled with a rope that exerts a force of 60. lb at an angle of 15 degrees with the horizontal. If the coefficient of kinetic friction is .35, what is the kinetic friction?

Homework Statement Questions are attached to this thread. Homework Equations P =mv (P is momentum) P = F/A (P is pressure) F = deltaP/delta t (P is momentum) The Attempt at a Solution I have managed to do questions a-e which I was very happy with but then moving onto the extension has made me...

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 KE = 0.5mv^2 Kinetic energy = change in momentum = mv2-mv1 The Attempt at a Solution Im not sure how to go about this...

Homework Statement Assuming uniform distribution. What must be the size of a cubical element of volume in the container so that the number of particles in each volume element may vary by 0.1% when the gas is as standard conditions. Probable deviation is given by N^(1/2) where N is the number of...

Homework Statement A closed vessel contains liquid water at equilibrium with its vapor at 100C and 1 atm. 1 gram of water vapor occupies 1670cm^3. Hvap = 2250Jg^-1. How many molecules are there per cm^3 of vapor?How many vapor molecules strike each cm^2 of liquid surface per second? Homework...

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...

I know this has been asked before: "Why is there a negative in the Lagrangian: L = T - V" I have read the answers and am not happy with them so I tried to formulate my own justification and now ask if anyone could comment on it? First, I am not happy with those who say "Because it works and...

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...

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?

Hello all, i have been asked a question about a lump of iron being warmed, and to calculate the difference between enthalpy and internal energy. I did some algebra and found that the change in the product pV , in the case of a liquid would suffice. But, since the volume doesn't change (Assumed...

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...

Hi - I have written a Fortran 'beginner' program to find the kinetic energy matrix for a simplistic non-relatavistic, 1-D, radial Schrodinger system - using the Lagrange - Laguerre Mesh method. Firstly, I have verified that my roots for the Laguerre poly ##L^{\alpha}_{N}(x_{i}) = 0## are...

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...

Homework Statement https://s2.lite.msu.edu/res/msu/perl_author/MI3/CH7/IMAGES/MI3_7P32.png The figure shows a potential energy curve for the interaction of two neutral atoms. The two-atom system is in a vibrational state (i.e., a total energy state) indicated by the heavy solid horizontal line...

Homework Statement At a waterpark, sleds with riders are sent along a slippery, horizontal surface by the release of a large, compressed spring. The spring with a force constant k = 4300 N/m and negligible mass rests on the frictionless horizontal surface. One end is in contact with a...

Im confused about the different letters assigned to energy (in intro physics). SO far I've learned about gravitational potential energy (U) Elastic potential energy (U) electric potential energy (U) and kinetic energy (K) How do we differentiate between all the different trypes of energy? Why...

Can someone please explain me the direction of static friction? I know kinetic friction is always going against the motion of an object but for static friction it depends.

Homework Statement Calculate the average potential and kinetic energies for the electron in the ground state of hydrogen. Homework EquationsThe Attempt at a Solution I know that KE = E - <U(r)>. I know that E = (-KZ^2e^2)/(2a0) and I know that U(r) = -KZe^2/r but I can't figure out how to...

Does anybody can help solve point kinetic equation for one group of delayed neutrons in steps. I am looking forward to solve it by analytical methods. dn(t)/dt=ρ-β/l n(t)+ λC(t) dC(t)/dt= βi* n(t)/l- λC I would really appreciate your help as i am have to submit to clear this paper next week

Homework Statement a small lump of ice at 0 degrees celsius falls to the Earth's surface. when the hailstone hist the surface, all of the kinetic energy of the hailsotne is transferred to thermal energy in the ice. calculate the minimum speed of the hailstone so that it just melts when it hits...

Homework Statement So I'm trying to find the final velocity of a proton that is being accelerated by a particle accelerator, just before it collides with a particle. All I have is its kinetic energy just before collision: 4.7066×10^(-13) J. I thought I should use KE = 1/2 mv^2 but then...

Homework Statement Show that the quantization of angular momentum implies that the kinetic energy of the electron is quantized as K=nhforb/2, where forb is the frequency of rotation. Assume circular orbit. Homework Equations Radial acceleration: arad = v2/r = (4π2r/T = 2*π*v/Tr = nħ KE =...

Homework Statement Just a simple question, does Kinnetic enrgy applies to a bullet that has being shot?Homework Equations K=1/2 * m * v^2 The Attempt at a Solution N/A

Homework Statement in the question you're having to solve for this. A force is applied at a angle of 30 degrees on a object that weighs 12kg that is also moving at a constant velocity. kinetic friction is equal to .70 i am confused on how to find the Force applied to achieve a constant...

W_{total} = \delta K What about lifting a block upward? If you lift a 10kg block vertically and bring it to a rest, you are doing work on it but the velocity in the beg and the end is 0, thus the equation says the work done on it is 0. But isn't there potential energy? Does the equation not...

Homework Statement An electric motor is used to pull a 125 kg box across a floor using a long cable. The tension in the cable is 350N and the box accelerates at 1.2m/s2 (forward) for 5.0s. The cable breaks and the box slows down and stops. Calculating the coefficient of kinetic force? Given...

Homework Statement On cart with a mass of 371 kg and another cart with a mass of 495 kg are rolling toward each other. Just before they collide, the 495 kg cart has a speed of 2.09 m/s, and the 371 kg cart has a speed of 1.90 m/s. We will consider the friction between the cart wheels and track...

Homework Statement Calculate how much force you would have to apply to the crate to get it to go at constant speed up a 30 degree ramp. Homework Equations Using kinetic friction for equation. The Attempt at a Solution I couldn't find the formula for kinetic friction which also includes...

http://imgur.com/luj32IE 1. Homework Statement A skier starts from rest at the top of a smooth incline of height 20 m as in Figure 2. At the bottom of the incline, the skier encounters a horizontal rough surface where the coecient of kinetic friction between the skis and the snow is 0.21. (a)...

can kinetic friction cause a torque? (can it result in rotation) Or is it that only static friction can cause a torque? Can static friction do work on a rolling object? I think it can? because the rotational kinetic energy is increasing? is this right? HELP!

Homework Statement [/B] Our teacher has given us the weekend to go and work on the Egg Drop project. He's restricted us to 20g total mass and 6cm * 6cm * 30cm in size. Food, foam, bubble wrap is prohibited. Parachutes can be added but can not make it exceed 12cm * 12 cm * 30cm. So that's what...

Homework Statement This isn't a problem from a textbook or homework but just a general question. Say there's a car traveling in a circle and that the track has some coefficient of kinetic friction µ. What would make the car skid? Homework EquationsThe Attempt at a Solution I'm thinking that...

A sheet of metal in the shape of a triangle massing 10 kg per square meter is to be spun at an angular velocity of 4 radians per second about some axis perpendicular to the plane of the sheet. The triangle is a right triangle with both short sides of length 1 meter. (a) The axis of rotation is...

Homework Statement A 100 kg person in space throws a 1kg sphere away from their body. The sphere starts from rest and ends up traveling 10 m/s away from the person. What is the kinetic energy of the person and the kinetic energy of the sphere? Is kinetic energy conserved?[/B]Homework Equations...

Homework Statement A 15.0g bullet is accelerated from rest to a speed of 780m/s in a rifle barrel of length of 72.0cm a)Find the kinetic energy of the bullet as it leaves the barrel b)Use the work kinetic energy theorem to find the net work that is done on the bullet. (this problem had part...

Hi, I like to ponder basic physics puzzles to pass time in boring meetings on metro etc...but I have one that I don't understand and I am obsessing over it (to detriment of working out etc.) it should be easy but I don't understand. Problem: Imagine you have two blocks (Mass of Block 1 is...

Homework Statement A 1000N crate is being pushes across a level floor at a constant speed by a force (F) of 300N at an angle of 20 degrees below the horizontal, what is the coefficient of kinetic force? Homework Equations Fk= uk*N uk= Fk/N[/B] Fk=F2 The Attempt at a Solution in the back of...