Conservation of momentum Definition and 757 Threads

  1. colemc20

    Do Neutrinos Leave Tracks in Cloud Chambers?

    My only issue is what this would look like. I can't draw a respective picture.
  2. S

    Determining position of an object after inelastic collision

    Homework Statement A 39,000 lb truck A and a 3968 lb sports car B collide at an intersection. At the moment of the collision, the truck and the sports car are traveling with speeds vA = 70 mph and vB = 30 mph. Assume that the entire intersection forms a horizontal surface. Letting the line of...
  3. F

    Ballistocardiograph and conservation of momentum

    Hi, once again I'm probably asking a question that is more about human physiology than physics (I recently asked a question that had to do with hearing). I found a (definitely too hasty) reference to a ballistocardiograph in a high school textbook. So I got curious about the way this apparatus...
  4. J

    Railway/Cannon - Conservation of Momentum HW Problem

    Hello forum. I have a HW question that I don't fully grasp just yet. It was multiple choice and somehow I guessed the right answer based on the work I did complete, but I want to know how to get to the solution and which steps I'm leaving out. I'll follow the format to write out the...
  5. P

    Ice Skating conservation of momentum (conceptual problem)

    Homework Statement Two ice skaters have masses m1 and m2 and are initially stationary. Their skates are identical. They push against one another, as in Figure 7.11, and move in opposite directions with different speeds. While they are pushing against each other, any kinetic frictional forces...
  6. Np14

    Rocket: conservation of momentum

    Homework Statement A fireworks rocket is moving at a speed of 45.0 m/s. The rocket suddenly breaks into two pieces of equal mass, which fly off with velocities v1 and v2. What are the magnitudes of v1 and v2? Homework Equations Conservation of Momentum m1v1 + m2v2 = m1vo1 + m2vo2 The...
  7. P

    Conservation of momentum - trampoline

    English isn't my main language, so I apologize in advance if something is unclear. We are leaving air resistance out of this problem! 1. Homework Statement We are going to describe the force F from the trampoline on the Joe as F = kx, k is a spring constant. This is a model. 1. Joe drops...
  8. S

    Percent error in conservation of momentum lab confusion

    Okay, so I did an elastic collision with Vernier carts and magnets. The results seem pretty good. Cart one started with -0.1205 kg*m/s ended with +0.1027 kg*m/s Cart two started with +0.1174 kg*m/s ended with -0.1118 kg*m/s So Total before = -0.0031 kg m/s and total after = -0.0091 kg m/s. If...
  9. Mason Smith

    Question involving the conservation of momentum

    Homework Statement Homework Equations The conservation of momentum states that if there are no external forces acting on a system, then momentum is conserved (i.e., the momentum before an event is equal to the momentum after an event). (Note: We assume that the internal forces follow Newton's...
  10. B

    A Measurement and the Conservation of Momentum

    If you prepare a particle with a “relatively precise” momentum by the act of filtering or measuring its momentum. It’s state will collapse into a momentum eigenstate and the measured momentum will be the corresponding eigenvalue. The position state will now be nearly uniformly spread out and...
  11. J

    Conservation of Momentum (Explosion Kinematics)

    Homework Statement [/B] A 3200 kg space vehicle (including a launchable lifeboat) is traveling with a velocity of 300 m/s in a straight trajectory [East]. The lifeboat (200 kg) is fired at a speed of 1000 m/s [N of original trajectory]. a) After firing it is found that the horizontal...
  12. E

    Conservation of momentum and angular momentum

    Homework Statement 4 masses attached by a cross with no mass are spinning on a smooth table around the center of the cross. The distance between any mass to the center is L. The angular velocity is ω0. m1=m3,m2=m4 Suddenly, at t=0 (the time described in the picture), m4 disconnects from the...
  13. A

    Conservation of Momentum Space Ship Problem

    Homework Statement The payload of a spaceship accounts for 20% of its total mass. The ship is traveling in a straight line at 2100km/hr relative to some inertial observer O. When the time is right, the spaceship ejects the payload, which is moving away from the ship at 500km/hr immediately...
  14. K

    Conservation of momentum in two dimensions

    Homework Statement A bomb initially at rest is exploded into three pieces on a smooth, horizontal surface. Two pieces fly off at a 60° angle to each other, a 2.0 kg piece at 20 m/s and a 3.0 kg piece at 12 m/s. The third piece flies off at 30 m/s with an unknown direction. Determine the...
  15. P

    Final velocities of two objects in a 2D elastic collision

    Homework Statement An atomic nucleous of mass m traveling with speed v collides elastically with a target particle of mass 3.0m (initially at rest) and is scattered at 45o (a). What are the final speeds of the two particles? Advice: eliminate the target particle's recoil angle by manipulating...
  16. Akash47

    How Does the Velocity of a Raft Change When Four Men Jump Off Simultaneously?

    Suppose four men are on a square shaped raft.All have jumped mutually perpendicularly into the river from the raft at velocity 2m/s at the same time. What will be the velocity of the center of mass of the raft? The implied assumption is likely that the mass of the four men is same. I think the...
  17. L

    Simple Ice Skater with Conservation of Angular Momentum

    Homework Statement Not a HW problem, but a "me re-thinking things" problem. Please tell me where my thinking is flawed: You have an ice skater with no net external torques acting on him/her. (We are analyzing the time after they have to get an external torque on them by pushing off of the...
  18. Akash47

    What Will Be the Velocity of the Center of Mass of the Raft?

    Homework Statement Suppose your three friends and you are on a square shaped raft. You all have jumped mutually perpendicularly into the river from the raft at velocity 2m/s at the same time. What will be the velocity of the center of mass of the raft? Homework Equations Maybe,the law of...
  19. Krushnaraj Pandya

    Conditions for conservation of momentum

    Homework Statement Consider a classic wedge and block system, (block on top of wedge(inclination theta)). there is friction between the block and wedge (not enough to prevent block from sliding). All other surfaces are smooth. For the motion that follows after releasing the block from rest, is...
  20. R

    Physics 30 question about conservation of momentum

    Homework Statement A space person is motionless a distance of 500m away from the safety of the spacecraft . The person has exactly 11.32min of air left and the person's mass is 103.2kg, including equipment. The person throws a phaser at a velocity of 50.2km/h away from the spacecraft in order...
  21. C

    Other I can't solve questions related to conservation of momentum

    I'm a passout from school taking a gap year. I find the concept of conservation of momentum exceedingly difficult. Each question - and sometimes each part of a question, if a question has different parts - requires us to choose different systems each time. I look at the solution, and think I...
  22. jxj

    Isolating Variable in Equation for conservation of momentum

    Homework Statement So the problem is trying to isolate mA in the equation for momentum (only focusing on top formula, not bottom hehe) basically by solving the equation I assume. My teacher said because the vA and vB on the right were prime they could not be combined so I'm having trouble...
  23. jfizzix

    A Violating conservation of momentum and its resolution

    The process is known as counter-propagating Spontaneous Parametric Down-Conversion (CP-SPDC). In regular SPDC, a photon from a (pump) laser enters a transparent nonlinear crystal at rest, and gets converted into a pair of photons whose total energy and momentum add up to that of the original...
  24. G

    Maximizing rocket velocity - shoot fuel at once, or slowly?

    I stumbled upon a 3-year old article from Wired that poses this question on rockets: Suppose I have two rockets with a mass M and fuel mass m. Rocket A shoots all the fuel at once (again, like a nuclear propulsion engine) with a fuel speed of u and rocket B shoots two blobs of fuel—first a shot...
  25. M

    Conservation of momentum - with understanding

    I just want to state that i DID solve the problem. I just seek understanding of it. I'd be really grateful if someone could answer two of my questions at the end of this post. The problem I've solved here is just to show what I'm dealing with. 1. Homework Statement Object 1 is moving towards...
  26. S

    Conservation of momentum & energy

    Homework Statement Hi, I do not know how to resolve question 1d and 2d at all. I hope the rest is well resolved, not sure about 1c and 2c. Can someone check my work and help me resolve problem with this questions, please? Task A hammer of mass 1700kg is dropped 2.5m under its own in fluency of...
  27. J

    D’Alambert vs Newton’s second law?

    I’m a bit stuck with differentiating between the conservation of energy and D’Alambert. For a question I need to find the average resistance of the ground after it has been struck by an object. I chose to look at the equation as Ma + Mgh - Fr = 0. Can you advise if this is correct?
  28. E

    How do we know how long the force is acting on an object?

    Hey all, so I'm self studying and I came across this question: A ## 2 kg ## cart, traveling on a horizontal air track with a speed of ## 3 m/s##, collides with a stationary ##4 kg## cart. The carts stick together. The impulse exerted by one cart on the other has a magnitude of: A. ## 0 ## B...
  29. D

    Combining conservation of momentum and kinetic energy

    Hi everyone, hopefully someone will be able to point me in the right direction with this problem, I get as far as combining the two equations together and no matter how I rearrange them they don't seem to cancel nicely and leave me with an awful quadratic, I can find vx, but the question...
  30. valovato

    Momentum transfer from linear to angular motion

    I am trying to create a momentum trap to calculate the velocity of a projectile when it hits the trap. It essentially consists of a plate if known mass at the bottom of a pendulum of known radius. When the projectile hits the plate, the degrees that the pendulum rotates are recorded. I believe...
  31. Kate2018

    High School Physics Question -- Skateboarder Jumps & Conservation of Momentum

    Homework Statement Lee is riding on her 6 kg skateboard with a constant speed of 2 m/s. She jumps off of her skateboard and continues forward with a velocity of 4 m/s relative to the ground. This causes the skateboard to go flying forward with a speed of 18.5 m/s relative to the ground. What is...
  32. A

    Why Is the Angle 90 Degrees in Elastic Collisions of Equal Mass?

    Homework Statement Prove that in the elastic collision of two objects of identical mass, with one being a target initially at rest, the angle between their final velocity vectors is always 90 degrees. Homework Equations m1v1+m2v2 = m1v1'+m2v2' 1/2m1v1^2 +1/2m2v2^2 = 1/2m1v1'^2 + 1/2m2v2'^2...
  33. A

    Elastic collision heavy particle problem

    Homework Statement Suppose a heavy particle (mass m1) has an elastic head-on collision with a very light particle of mass m2 initially at rest. Show that if m1>>m2, the velocity of the projectile (m1) is practically unchanged, whereas the target particle (m2) acquires a velocity v2' = 2v1...
  34. T

    Confusion with "explosive" part, Conservation of Momentum

    Homework Statement A two-stage rocket is traveling at 4500 m/s before the stages separate. The 3000-kg first stage is pushed away from the second stage with an explosive charge, after which the first stage continues to travel in the same direction at a speed of 3000 m/s . How fast is the...
  35. F

    Conservation of Momentum With Changing Mass

    Homework Statement [/B] A rocket that starts at rest with mass M ejects exhaust at a given speed u. What is the mass of the rocket (including unused fuel) when its momentum is maximum? What is the mass when its energy is maximum? Homework Equations [/B] p = mv The Attempt at a Solution...
  36. K

    Conservation of Momentum Lab (Carts Collide and Stick Together)

    Homework Statement We did a lab where we had one cart with an unknown mass stationary on a friction-less surface. Another cart with a mass of 378.9g, was pushed down the track (which moves at a constant speed due to the friction-free surface) and collides with the second cart - so it is a hit...
  37. O

    I Photonuclear reaction & Conservation of momentum

    γ+2D ----> 1H + 1n In this photonuclear reaction, is it possible to write the momentum balance equation as it follows, MHvH = Mnvn It somehow seems to wrong to me, since the incoming photon has a certain momentum, which is not taken account in the balance equation. Thank you in advance.
  38. U

    Conservation of linear momentum in this system

    A pet mouse sleeps near the eastern edge of a stationary, horizontal turntable that is supported by a frictionless, vertical axle through its center. The mouse wakes up and starts to walk north on the turntable. Is the momentum of the system constant? i understand that the initial momentum is...
  39. Lukanol

    Conservation of momentum on relativistic collisions

    1. Homework Statement ( This question is from the textbook of Introduction to Elementary Particle Physics, written by Griffiths, on the problem set of Chapter 3 ) Particle A (energy E) hits particle B (at rest), producing particles C1, C2, ...: A + B → C1 + C2 + ... + CN. Calculate the...
  40. S

    Conservation of Momentum vs Energy

    Homework Statement Given a horizontal rod (parallel to x axis) and two disks attached near its ends symmetrically. The rods and disks are perfectly balanced i.e. the disks have same mass and density. The system's center of mass is exactly at geometric center of the rod (since its balanced)...
  41. C

    Other Physics EE (Extended Essay) Advice: Conservation of momentum

    I am not sure if I am at the right place and I hope that I am... For my EE I want to do an investigation on something related to pool table and games so it will definitely be related to momentum. And one of the common techniques in pool games is that the player aims the ball on the rail of the...
  42. S

    Conservation of Momentum for Magnets

    Homework Statement Given 2 magnets of equal weight (w0) and each with a magnetic strength (t0) placed inside a straight hollow cylindrical tube. One of the magnets is attached to one end of the tube and the other magnet is free to move inside the tube. The other end of the tube is open to...
  43. B

    Conservation of Angular Momentum of Train on Disk

    Homework Statement A horizontal plywood disk with mass 6.90 kg and diameter 1.14 m pivots on frictionless bearings about a vertical axis through its center. You attach a circular model-railroad track of negligible mass and average diameter 1.04 m to the disk. A 1.40 −kg , battery-driven model...
  44. J

    Final speed and direction after a collision (elastic+inelastic)

    Homework Statement A billiard ball moves at a speed of 4.00 m/s and collides ELASTICALLY with an identical stationary ball. As a result, the stationary ball flies away at a speed of 1.69 m/s. Determine a. the final speed and direction of the incoming ball after the collision b. the direction...
  45. I

    Two-ended rocket - Conservation of Momentum

    Homework Statement A two-ended "rocket" is initially stationary on a frictionless floor, with its center at the origin of an axis. The rocket consists of a central block C (of mass M=6 kg) and blocks L and R (each of mass m = 2 kg) on the left and right sides. Small explosions can shoot either...
  46. S

    Conservation of Work/Momentum of Puck Sliding Off Plate

    Homework Statement I saw this problem from a few years ago here on Physics Forum (https://www.physicsforums.com/threads/work-energy-theorem-problem.823990/) and wanted some clarification. Here is the problem: A curved plate of mass M is placed on the horizontal, frictionless plane as shown...
  47. Amaterasu21

    Kinetic theory of gases: rebound speed and force questions

    Hi everyone, I remember years ago at school memorising the derivation of the formula for pressure in the kinetic theory of gases, as explained in this Youtube video: Thinking a little more deeply about this derivation there are two things I don't get: 1) At 0:53, the video says the molecule...
  48. Richardparker800

    Need help with collision and conservation of momentum problem

    Homework Statement Two blocks move along a horizontal frictionless surface and collide head-on with each other. The mass of the first block, moving to the right with speed v is m, and the mass of the second block moving towards the left with speed 3v is 2m. After the collision, the block of...
  49. Pbaseball

    Conservation of momentum and Moment of Inertia

    Hello everyone, I'm needing help understanding how to take the conservation of momentum equation and substitute moment of inertia inplace of mass in the equation. I understand this is a linear equation and I'm trying to incorporate angular momentum. I just want to determine the speed of the ball...
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