Momentum and energy Definition and 164 Threads

Could someone give me some deeper insight why we need to have momentum and energy to describe motion? Kinetic energy is only the square root of momentum divided by two times the mass of the particle. Why the need for this extra entity energy? I know that energy is a scalar and momentum is a...

Consider an ideal case of a mass m1 moving at constant velocity v1 on a frictionless surface, colliding with another masss m2 at rest. After collision, can someone tell me if it is possible for m1 to move off at -v1 while conserving the momentum and energy of the entire system? This is quite a...

Momentum and Energy i think?? Homework Statement Block 1 of mass m1 slides from rest along a frictionless ramp from height h = 3.10 m and then collides with stationary block 2, which has mass m2 = 5.00m1. After the collision, block 2 slides into a region where the coefficient of...

I want to know what exactly is the free-electron laser power beaming system that will be used in our future Space elevator and how the conservation of energy and momentum is associated with this project that NASA will launch. ? Other info: I am taking grade 12 university level physics; All...

http://hyperphysics.phy-astr.gsu.edu/hbase/inecol.html When a block in motion(M1) collides with a a stationary object (M2) in a perfectly inelastic collision, the fraction of KE final/KE initial can be modeled as M2/M1+M2. My question is if M2 has to be stationary for this equation to...

In an isolated system, momentum is conserved. I understand this. However, I also learned that that the motion and energy of the particles inside of an isolated system is defined by the average kinetic energy (temperature). Do we have to assume that every collision is elastic and that kinetic...

Homework Statement I have a 2D square well with sides a. What is the minimum momentum and energy for this well? Homework Equations Minimum momentum given by Δp≈ℏΔx and Δp≈ℏΔy Minimum energy given by ΔE≈ℏΔt This might be right. It says to consider the Schrödinger Equation in 2D. I've never...

Homework Statement Determine the energy and change in orbital speed required for the Earth to escape from its orbit around the Sun. Homework Equations I guess: Change In E = E total of o - E total of s (Egs) E total of orbit = (0.5)Eg of oribit The Attempt at a Solution Don't really know...

Homework Statement A uniform rod has a mass 2m and a length l, and it can spin freely in a horizontal plane about a pivot point O at the center of the rod. A piece of clay with mass m and velocity v hits one end of the rod, and causes the rod-clay system to spin. After the collisions...

1. Two spheres having masses M and 2M and radii R and 3R, respectively, are simultaneously released from rest when the distance between their centers is 12R. Assume the two spheres interact only with each other and we wish to find the speeds with which they collide. Write an equation from one of...

I recently did an experiment in class that involved two parts, 1) the collision of 2 metal pucks 2) the collision of 2 magnetic pucks following the analysis, i discovered that in part 1, 75% of the original kinetic energy, and 93% of the original momentum was conserved after the collision...

momentum and energy two sled questions for physics... I have tried to solve these questions but sleds to me are just very confusing and hard...I really need help with this. A sled starts from rest at the top of the frictionless, hemispherical, snow-covered hill shown in the figure. a)...

Homework Statement Hi, new to the forums and I was wondering if someone could help me figure out what I am doing wrong. Thanx in advance. Gayle runs at a speed of 4.38 m/s and dives on a sled, which is initially at rest on the top of a frictionless snow-covered hill. After she has descended a...

Homework Statement A gamma ray photon with wavelength=2.0 * 10^-15m is traveling in the positive x direction undergoes a one dimensional collision with a stationary proton. a.) find the relativistic momentum and energy of the photon and proton before the collision. b.) assuming the...

A 5.00 g bullet is fired into a 6.00 kg block, which is suspended from a string 1.00 m long. The string deflects through an angle of 12.0°. How fast was the bullet moving?a Transitional KE = ½ mv2 Rotational KE = ½ I2 Elastic PE = ½k L 2 I'm not sure those are the right formulas...

Hello everyone, Let's say there was gun and a bullet with a mass of 1kg at rest. The bullet and guns speeds were 2 m/s in opposite directions after firing if I right the equations. Kinetic energy 0.5m1v12 + 0.5m2v12 = 0.5m1v22 + 0.5m2v22 Why doesn't this equation work when objects are at...

Homework Statement Jane, whose mass is 50 kg, needs to swing across a river having width D (50 m). She must swing into a wind with force F = 100 N while on a vine of length L (40 m) and initially making an angle theta of 50 degrees with the vertical. What minimum speed must Jane have to just...

"high school" algebra -> relativistic conservation of momentum and energy Homework Statement Consider a head-on, elastic collision between a massless photon (momentum po and energy Eo) and a stationary free electron. (a) Assuming that the photon bounces directly back with momentum p (in the...

Change in momentum of a ball Please note, instead of making a new thread I just edited my new question into this thread Homework Statement A ball is rolled into a wall and bounces back at the same speed, the change in momentum is? Homework Equations Ein = Eout The Attempt at a Solution...

Homework Statement A ball, with mass m_{1}=6 kg and speed v_{0} (unknown) hits an inclined plane (as shown) of mass m_{2}=42 kg at rest on a frictionless floor. there is no friction between the ball and the plane. the angle \beta is 10 degrees. Question: what is the value of \alpha?2. Diagram...

Basic Momentum and Energy! and time! 1. A 5.36 g bullet moving at 681.8 m/s penetrates a tree trunk to a depth of 3.79 cm. a) Use work and energy considerations to find the magnitude of the force that stops the bullet.Answer in units of N. for this i did 1/2mv^2=w=fd so...

Basic Momentum and Energy! 1. (part 1 of 2) A 4.78 g bullet moving at 510.8 m/s penetrates a tree trunk to a depth of 4.93 cm. a) Use work and energy considerations to find the magnitude of the force that stops the bullet. Answer in units of N. for this i did 1/2mv^2=w=fd so...

Basic Momentum and Energy! Note: Take East as the positive direction. A(n) 88 kg fisherman jumps from a dock into a 123 kg rowboat at rest on theWest side of the dock. If the velocity of the fisherman is 4.1 m/s to the West as he leaves the dock, what is the final velocity of the fisherman...

1. (part 1 of 3) A 25 kg child is riding a 6.4 kg bike with a velocity of 4.2 m/s to the northwest. a)What is the total momentum of the child and the bike together? Answer in units of kg · m/s. 2. (Part 2 of 3) b) What is the momentum of the child? Answer in units of kg · m/s. 3. (part 3...

part (1 of 3 ). A 15 metric ton train moves toward the south at 70 m/s. At what speed must it travel to have five times its original momentum? A metric ton is 1000 kg. Answer in units of m/s. and Part (2 of 3 ). At what speed must it travel to have a momentum of 5 × 105 kg · m/s...

Homework Statement A Hunter shoots a 500g arrow at a 2 kg bird perched on a tall tree growing on flat, level ground. The arrow is launched from ground level with a speed of 40 m/s at an angle of 30 degrees above the horizon. It is traveling horizontally when it embeds in the bird. How far from...

Homework Statement Blocks a (mass 3.50 kg ) and b(mass 10.00 kg ) move on a frictionless, horizontal surface. Initially, block b is at rest and block a is moving toward it at 2.00 m/s . The blocks are equipped with ideal spring bumpers. The collision is head-on, so all motion before and...

Homework Statement a) At t=1 second, a 0.5 kg cart is at x=0.5 m, traveling at 0.5 m/s. At t=3 seconds, the cart is at 1.4 m, traveling at 0.4 m/s. What is the acceleration due to friction, the frictional force and the work done by friction? What is the change in kinetic energy of the cart...

a) At t=1 second, a 0.5 kg cart is at x=0.5 m, traveling at 0.5 m/s. At t=3 seconds, the cart is at 1.4 m, traveling at 0.4 m/s. What is the acceleration due to friction, the frictional force and the work done by friction? What is the change in kinetic energy of the cart? b) If a cart of mass...

Homework Statement A nucleus originally at rest splits into two fragments of unequal mass. The fragment with smaller mass has a larger 1.momentum 2.speed 3.Kinetic energy A. 1only B. 3only C. 1&2 only D. 2&3 only E. 1,2 &3 The Attempt at a Solution well, i can figure out the...

Homework Statement In a certain reference frame, a particle with momentum of 7 MeV/c and a total energy of 9 MeV. Determine the mass of the particle. I did not mistype this problem, this is the way it appears on my assignment. Homework Equations Total Relativistic Energy...

Homework Statement Each equal ball shown in figure 1 is suspended on a separate inextensible string of equal length R. The strings are attached to a rigid support and the attachment points are separated by a distance equal to the diameter of the balls. Both balls are initially stationary in...

Hello everyonea. I was studying special relativity and i got stuck on an example. Here it is:'to an observer,two bodies of equal rest mass collide head on with equal but opposite velocities 0.8c and cohere. To a second observer,one body is initially at rest. Find the apparent velocity of the...

I've been presented with these concepts, and the first time i saw them i thought they were just mathematical mambo-jumbo, but of course i didn't gave much importance to these thoughts. I've been constructing an idea of these after seeing how they behave in different circumstances, but really, i...

[b]1. a. An electron of rest mass (0.511Mev) is accelerated in a linear accelerator so it has a total energy of 40 Gev. i).What fraction of the total energy is kinetic energy? ii).what is the reletivistic linear momentum of the electron? iii).What is its relativistic mass? b.A particle of...

Homework Statement A body of 2M(KG) mass at velocity V collided with a body of mass M(KG) at rest. The first body after collision has a velocity ao 1/3V , and the second moves at 4/3V. Verify both laws of conservation of linear momentum and energy with explanation. Homework Equations...

Homework Statement Two air track gliders of mass 0.30kg and 0.20 kg are moving towards each other with speeds of 0.50 m/s and 1.0m/s respectively. Take the direction of the more massive glider as positive. A) if the collision is elastic, find the velocity of each glider after the collision...

Homework Statement A bullet of mass 0.125 kg traveling horizontally at a speed of 250 m/s embeds itself in a block of mass 3.5 kg that is sitting at rest on a nearly frictionless surface. (a) What is the speed of the block after the bullet embeds itself in the block? v = ? m/s (b)...

Hi! I need an explanation: Is the momentum operator for a free particle with a definite momentum and energy the same as what we know as the momentum operator in general? Is it just -ih/2PI()*partial/partial_x? With the justification that since the momentum is definite, delta p is 0...

So this may be an easy question, I'm not sure, but I could not find an answer online. Basically here is the scenario. There are two balls, one has a mass of 1g and the other has a mass of 100g. The 1g ball is traveling at 10m/s, and strikes the other ball. According to momentum, m1v1=m2v2...

Homework Statement The non-moving 10-kg block is held frictionlessly inclined at 30 degrees by a stop at point A . A 0.010-kg bullet is moving at 300 m/s hits the block and embeds into it. http://img386.imageshack.us/img386/9305/68906392wf8.jpg I'm unsure which is the horizontal...

Homework Statement A cube of mass m slides down a circular path of radius r cut into a larger block of mass M. M rests on a table, and friction is ignored. Both blocks start at rest and m starts at the top of the circular path. What is the velocity v of the the small cube as it leaves the...

Homework Statement A 64kg student is standing in the middle of a frozen pond with a frictionless surface while carrying 2 books, a physics book with a mass of 2.5kg and a biology book with a mass of 3.5kg. The physics book is thrown with a speed of 6m/s relative to the student to the right...

Homework Statement An isolated system is initially at rest. Is it possible for parts of the system to be in motion at some later time? Explain. Homework Equations N/A The Attempt at a Solution My guess is no because if the system is at rest, the only way the system could get...

An isolated system is initially at rest. Is it possible for parts of the system to be in motion at some later time? Explain. When driving a golf ball, a good 'follow-through' helps to increase the distance of the drive. Explain why this technique allows you to hit the ball farther.

Homework Statement We measure a comet at perihelion to have a radial distance r1 and a velocity v1. Find the radial distance and velocity when it reaches aphelion. Homework Equations L=mvr=I*\omega E=.5mv^2+U The Attempt at a Solution My professor skipped the chapter on Newton's...

Homework Statement A pendulum consists of a 0.5 kg bob attached to a string of length 1.6 m. A block of mass m rests on a horizontal frictionless surface. The pendulum is released from rest at an angle of 53° with the vertical and the bob collides elastically with the block. Following the...

photon momentum and energy is a frequent topic on the forum. consider a tardyon (u<c) the momentum of which transforms as p=gp'(1+V/u') (1) E=gE'(1+Vu'/c^2) (2) state that special relativity theory ensures a smooth transition from the properties of the tardyon to the properties...

A small block of mass m1 = 0.300 kg is released from rest at the top of a curved wedge of mass m2 = 2.00 kg, which sits on a frictionless horizontal surface as in Figure P6.59a. When the block leaves the wedge, its velocity is measured to be 4.00 m/s to the right, as in Figure P6.59b...

I had a couple homework questions that I was having trouble solving..I was hoping someone could help me out.. 1. A car of mass 1430 kg traveling at 26 m/s is at the foot of a hill that rises 120 m in 3.8 km. At the top of the hill, the speed of the car is 10 m/s. Find the average power...