Conservation of momentum Definition and 757 Threads

  1. T

    Conservation of momentum problem

    Homework Statement A 1200kg car traveling initially with a speed of 25m/s in an easterly direction crashes into the rear end of a 9000kg truck moving in the same direction at 20m/s. The velocity of the car right after the collision is 18m/s to the east. 3.4.1) What is the velocity of the...
  2. D

    Principle of conservation of momentum question

    [b]1. Somebody help explain how to do this for me, am not looking answer, an explanation so i can solve it would be great. A space vehicle traveling at a velocity of 7000km/h separates into two sections of mass 1100kg and 200kg. the two parts continue moving in the same direction with the...
  3. Q

    What Is the Velocity and Net Force After Two Football Players Collide?

    Homework Statement Football player 1 with a mass of 110kg is moving at 8.0m/s [S] when he crashed into football player 2 with a mass of 105kg, moving at 12m/s [N]. During the tackle, football player 1 hangs onto football player 2, giving them the same velocity during the 0.3 second...
  4. T

    Action and Reaction or Conservation of Momentum?

    Basically, when a natural frequency acts on coke bottle, It resonates. During the resonance, the lump of air in neck of it goes under simple harmonic motion. It goes in and out the bottle, increasing and decreasing pressure of cavity of coke periodically. When air goes inside the bottle, the...
  5. T

    Help with a conservation of momentum problem

    A 15 g bullet is fired is fired with a velocity of 220 m/s from a 6.5 kg rifle. What is the recoil velocity of the rifle? That is the problem I think i use the formula... This half of the equation equals zero due to the initial velocity equaling zero = Mass of the gun*Velocity of the...
  6. S

    Conservation of Momentum Question.

    Homework Statement An 800 kg airplane traveling at a velocity of 120 m/s [30o N of E @ 20o above the horizon] collides with a stationary 1200 kg helicopter. If the velocity of the airplane after the collision is 65 m/s [40o N of E @ 60o above the horizon] what is the final velocity of the...
  7. 7

    Pair production - conservation of momentum VS conservation of energy

    Allover the web i am only seeing a statement similar to this: "Pair production is not possible in vaccum, 3rd particle is needed so that conservation of momentum holds." Well no one out of many writers shows, how to prove this matematically. So this is what interests me here. First i wanted...
  8. H

    Conservation of momentum - falling from hovering helicopter

    Homework Statement Bronco dives from a hovering helicopter and finds his momentum increasing. Does this violate the conservation of momentum? Homework Equations p(before) = p(after) The Attempt at a Solution no, this does not violate the c.o.m, because it is a closed system of...
  9. N

    Conservation of Momentum in Elastic Collision at Angles

    Homework Statement If a Mass let's say a Ball Bearing A with a velocity of 2ms-1 and a mass of 2Kg hits two other ball bearing B & C which is not moving with ball bearing B & C each has a mass of 1kg each. What will happen to ball bearing B & C? Please see attached picture i have the question...
  10. N

    Help test tmrw elastic collision and conservation of momentum problem?

    Block 1 moves with speed of 10m/s to right. It hits block 2 which has twice the mass of block 1 and speed of 5m/s to right. compute the magnitude and direction of block 1 for a perfectly elastic collision. solution: u1 = 10m/s u2 = 5m/s m1v1 + m2v2 = m1u1 + m2u2 ----> v1 + 2v2 = u1 + 2u2 ...
  11. A

    Conservation of momentum theory question

    Hi, I was wondering how one could know when velocity would be in the opposite direction in a momentum question. For example, two skaters are skating together (as one) at the same speed. Skater A pushes skater B and B moves at 13m/s. Find the speed of skater A. I found it and it's the...
  12. T

    Basic theory behind conservation of momentum and impulse.

    Conservation of momentum does not hold true? Homework Statement Here is the problem. State 2 is shown in the picture, it is right before impact. State 3 is after impact. I used conservation of momentum of the entire system (rod and table. However as you can see it shows us that the...
  13. D

    Conservation of Momentum - Collisions

    Homework Statement A truck (4 000 kg) runs a red light and enters an intersection traveling at 81 km/h [E]. The truck collides with a car (2 000 kg) that was traveling at 54 km/h [N20oW]. Immediately after the collision the truck was traveling at 60 km/h [N 30o E]. Determine the velocity...
  14. N

    Conservation of momentum, elastic collision problem? Help

    Two titanium spheres approach each other head-on with the same speed and collide elastically After the collision, one of the spheres, whose mass is 300 g, remains at rest. What is the mass of the other sphere? What i did: m1v1 + m2v2 = m1u1 - m2u2 v1 = 0 b/c at rest m2v2 = m1u1 - m2u2 m2v2...
  15. N

    Conservation of momentum, elastic collision, find other mass? help

    conservation of momentum, elastic collision, find other mass? help! Two titanium spheres approach each other head-on with the same speed and collide elastically After the collision, one of the spheres, whose mass is 300 g, remains at rest. What is the mass of the other sphere? What i did...
  16. C

    Conservation of Momentum Question

    Hello, Here is the situation I have been pondering: A person is sitting in a shopping cart at rest. By throwing their weight forward they are able to cause the shopping cart with them inside to move. My question is how this works. If momentum is conserved unless an external force acts...
  17. L

    Kinetic energy along with conservation of momentum

    Homework Statement a hockey player of mass 80 kg was skating at a velocity of 7.5 m/s [E 20 S] when he accidently hit a linesman who was just standing on the ice. The mass of the linesmass is 90 kg and his velocity after the collision was 3 m/s [E 30 N] find. a) the velocity of the hockey...
  18. N

    Conservation of Momentum in a Girl and Plank System

    conservation of momentum?? Homework Statement A 45.0 kg girl is standing on a 156 kg plank. The plank, originally at rest, is free to slide on a frozen lake, which is a flat, frictionless surface. The girl begins to walk along the plank at a constant velocity of 1.51 m/s relative to the...
  19. 0

    Extremely Hard Conservation of Momentum Problem

    Homework Statement A 0.750kg block of wood is attatched to a spring with k = 300N/m. A 0.0030kg bullet is fired into the block, and the spring is compressed 0.102m. Calculate the velocity of the bullet before the collision. Is this elastic or inelastic? Homework Equations How do you do...
  20. L

    Bullet and target- conservation of momentum and energy

    Homework Statement A man aims his gun vertically and shoots a 0.245 kg target, which is positioned on a telephone pole. The bullet has a mass of 0.055 kg and is traveling at a velocity of 850 m/s upwards just before it hits the target. The bullet passes through the target, emerging with a...
  21. N

    Elastic collision with Conservation of momentum problem?

    elastic collision with Conservation of momentum problem? i need help with part b. Two titanium spheres approach each other head-on with the same speed and collide elastically, After the collision, one of the spheres, whose mass (m1) is .3 kg, remains at rest. (a) What is the mass of the other...
  22. M

    Deductively proving the conservation of momentum

    I won't go into all the details but, to summarize, I'm planning on writing something on the philosophy of science and I was wondering if it's possible to deductively prove, that is without the use of observation or experience, the conservation of momentum. I know that it's possible to prove it...
  23. N

    Conservation of momentum problem. Very confused Speed of Bullet?

    In Fig. 9-58a, a 3.50 g bullet is fired horizontally at two blocks at rest on a frictionless table. The bullet passes through block 1 (mass 1.20 kg) and embeds itself in block 2 (mass 1.80 kg). The blocks end up with speeds v1 = 0.630 m/s and v2 = 1.40 m/s (Fig. 9-58b). Neglecting the material...
  24. B

    Conservation of momentum continous mass flow freight cart.

    Homework Statement I am having difficulty understanding why in 2.1 Worked Example Coal Car on page 3 One can use the initial time as time = 0, but 2.2 Worked example on page 4 they start the initial time at an arbitrary time t. Homework Equations The Attempt at a Solution
  25. B

    Conservation of Momentum problem.

    Homework Statement Example 17.5.1 page 9 : I understand everything but one assumption that is made. " We can use this to determine the speed of the larger piece after the collision. Since the larger piece takes the same amount of time to return to the ground as the projectile originally...
  26. A

    LAB: Ballistic Pendulum + Conservation of Momentum

    I'm doing the prelab questions which require conceptual questions, not so much of math. The experiment is a typical ballistic pendulum lab - you'd shoot a paintball twoard a pendulum bob, and you measure the height the pendulum bob reaches after collision to calculate the related velocities...
  27. 0

    Conservation of Momentum v.s. Conservation of Energy

    Hi, I'm new to this forum. So I do not understand how, in an inelastic system, momentum is conserved. Consider this problem: Tarzan swings from a branch 4 meters up and picks up jane how far can he swing up the other side? He weighs 100kg and is standing still on the branch. He jumps...
  28. M

    Collision and Conservation of Momentum

    Homework Statement Show that you can measure the magnitude of the velocity vectors which have units of distance/time with a ruler that measures distance, if a certain condition is met. What is this necessary condition.Use the Equation and Figure to prove below that this can be done...
  29. A

    Conservation of Momentum problem

    Homework Statement A 1500-kg car is traveling north at 25 m/s when it strikes a 2000-kg car traveling east at 20 m/s. The cars stick together after the collision. What is the final velocity of the two cars? Homework Equations m1v1 + m2v2 = (m1 + m2)vf The Attempt at a Solution...
  30. R

    How Does Momentum Conservation Apply in Nuclear Disintegration?

    Conservation of Momentum? An unstable nucleus of mass 2.7 x 10-26 kg, initially at rest at the origin of a coordinate system, disintegrates into three particles. One particle, having a mass of m1 = 1.0 x 10-26 kg, moves in the positive y-direction with speed v1 = 4.8 x 106 m/s. Another...
  31. T

    Conservation of momentum and energy problem-Two particles conected by string

    Homework Statement Two particles A and B each of mass m are attached by a light inextensible string of length 2l .The whole system lies on a smooth horizontal table with B initially at a distance l from A.The particle at end B is projected across the table with speed u perpendicular to...
  32. K

    Conservation of Momentum of a shot bullet

    Homework Statement If a 30 g bullet is shot with a velocity of +300 m/s from a 7.5 kg gun, what is the recoil velocity of the gun? m1 = 0.03 kg v1 = 300 m/s m2 = 7.5 kg Velocity initial for both objects is 0.0 m/s Homework Equations (m1 + m2)(v) = (m1v1) + (m2v2) The Attempt...
  33. S

    Law of conservation of momentum problem

    A boat is 4 m long and there is a person standing on one end of it. He walks across to the other end of the boat. The mass of the person is 70 kg and the mass of the boat is 200 kg. Find the distance moved by the boat. Not very sure of my answer. Need help solving this.
  34. A

    Atom Vibration: Temperature & Conservation of Momentum

    I know this question is probably fairly basic but I had a hard time finding an answer on google. Does a single atom vibrate/jiggle/oscillate if it has a temperature (ie is not at absolute zero)? Is this vibration random in direction? If it is random, wouldn't this violate the law of...
  35. D

    Conservation of momentum and uncertainty.

    In situations where the momentum of particles is only known to some degree of certainty, what can you say about the total momentum of the system? Is it only conserved to an extent that it always falls in a certain range?
  36. N

    Conservation of Momentum & Quantity of Motion: Examples Needed

    Hi everyone! I need some examples about Conservation of the quantity of motion and of the momentum of the quantity of motion to verify that these physical quantities are conserved in isolated environment. Sorry for my bad english
  37. S

    Simple Vector Question Related to Conservation of Momentum

    Homework Statement A spaceship of mass M is traveling in deep space with velocity vi = 20 km/s relative to the Sun. It ejects a rear stage of mass 0.2 M with a relative speed u = 5 km/s. What then is the velocity of the spaceship? Homework Equations conservation of momentum, p = mv let U be...
  38. S

    Understanding Conservation of Momentum

    Sir , Can you please explain me " The conservation of mometum " with an example ? I am not able to understand the concept of CONSERVATION OF MOMETUM . So please help me Sir . I will be very thankful .
  39. C

    Car Collistion using conservation of momentum

    Homework Statement Two Cars Yellow: Moving South Green: Moving West Green car stop in center of intersection and gets hit on from south bound Yellow Car They collide, at intersection, find initial velocity, impact velocity and momentum (this confuses me) Yellow Mass - 1356 kg Green...
  40. A

    Collision, conservation of momentum and energy

    In a collision the colliding particles will in general have different velocities at different instants of time. Overall this means that the particles can easily cover different distances during a collision and thus have different amounts of work done on them. My question is: Will the difference...
  41. I

    Conservation of momentum problem from SAT II

    Hello, I am having trouble understanding this short problem from a Kaplan SAT II prep book. Here it is: A 60 kg man holding a 20 kg box rides on a skateboard at a speed of 7 m/s. He throws the box behind him, giving it a velocity of 5 m/s. with respect to the ground. What is his velocity...
  42. A

    Conservation of momentum problem

    A body with a mass of M is on a friction-free horizontal floor. The shape of the body is a half circle with a radius of R. A mass of m is put at the left edge of M and is released from rest. the mass m rolls on the half circle with no friction. Is there conservation of momentum during the...
  43. N

    Conservation of Momentum; finding the angular speed of a Neutron star

    Homework Statement Under some circumstances, a star can collapse into an extremely dense object made mostly of neutrons and called a neutron star. The density of a neutron star is roughly 10^{14} times as great as that of ordinary solid matter. Suppose we represent the star as a uniform, solid...
  44. F

    Law of conservation of momentum

    I am confused over the law of conservation of momentum. The definition says that "if there is no external force on the system then there is no impulse and the momentum is unchanged" However under the definition of Impulse Note "F is for all external forces including forces due to gravity and...
  45. S

    Conservation of momentum of two particles

    Two particles A and B of mass 4 kg and 2 kg respectively are connected by a light inextensible string. The particles are at rest on a smooth horizontal plane with the string slack. Particle A is projected directly away from B with speed um s−1. When the string goes taut the impulse transmitted...
  46. W

    Proving Conservation of Momentum

    Hey guys I've a theory that my physics lecturer wants me to prove, basically I have to prove the conservation of momentum which is easy enough but it's in a specific situation which happens to be a bouncing ball. So obviously I know relevant SUVAT equations and I know how to work out change in...
  47. J

    How GR Resolves the Conservation of Momentum and Energy

    We know that the reason energy and momentum are conserved is b/c of Noether's theorem...time translational invariance implies energy conservation and space translational invariance implies momentum conservation. Now in a curved spacetime you can still form conserved quantities - energy and...
  48. W

    Conservation of Momentum and Relative Velocity

    Homework Statement A 55kg student stands on a 4.6 kg surfboard moving at 2.0 m/s [E]. The student then walks with a velocity of 1.9 m/s[E] relative to the surfboard. Determine the resultant velocity of the surfboard, relative to the water. Neglect Friction. Answer: 0.25 m/s[E] Homework...
  49. S

    Conservation of momentum ( I Think )

    Homework Statement A car ( mass 1500kg) is traveling at 40km/hr when it instantaneously starts to accelerate at a rate of 1.5ms-2 it then cruised at this new velocity before it collides with a stationary vehicle two third its mass at a set of traffic lights and the two vehicles move off...
  50. N

    Conservation of momentum: Student walking on surfboard find resultant velocity

    Homework Statement A 55 kg student stands on a 4.6 kg surfboard moving at 2.0 m/s [E]. The student then walks with a velocity of 1.9 m/s [E] relative to the surfboard, relative to the water. Neglect Friction. Answer: 0.25 m/s[E] Homework Equations m1vi1 + m2vi2 = m1vf1 + m2vf2 The...
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