Conservation of momentum Definition and 757 Threads

I was watching a show on the science channel called "Alien Encounters". Well in one of them they showed a ship that looked as if it was propelling itself by firing a laser at it's solar sail. Now I am pretty sure that from what I understand about physics, that would not be possible. Correct if...

Hi, I just want to understand this concept a bit better. The law states that momentum is conserved when there is no external force acting on the system. Now consider this situation where two cars of equal mass and moving at equal speed collide head-on to come to rest. Would the...

Hi all. I am learning physics and I have the following problem. Suppose there is a ball of mass m traveling with velocity v towards a wall at rest. The ball bounces back and it's now at velocity -v. Since the wall is always at rest, it follows that the total momentum before the collision was...

Homework Statement A man of mass 65kg is running at speed of 4.9m/s, jumps into a rowboat of 88kg that is drifting without friction in the same direction at a speed of 1.2m/s. when the man is seated in the rowboat, what is the final velocity of the boat? Homework Equations Momentum...

Homework Statement Ok so a block is suspended by two massless strings. A bullet hits the block and gets imbedded in it and moves. Bullet has speed v block has mass M. Bullet has mass m A second question if that is a system isolated if gravity acts on it and related to that is if mechanical...

Homework Statement A curling stone with a mass of 20kg slides across the ice at 1.5m/s. It collides head on with a stationary 0.16kg hockey puck. After the collision, the puck's speed is 2.5m/s. Assume the motion occurs in the horizontal direction. What is the stone's final velocity? Follow...

Homework Statement Ma=2900kg Mb=730kg Va1=11m/s Va2=9m/s Vb1=30m/s Vb2=32.54m/s ∅=49.14 Homework Equations (2900kg)(49.14)+(730kg)(30m/s*cos(25))=2900kg(9m/s)(cos(α))+730kg(32.54m/s)cos(β) and (2900kg)(11m/s)+730kg(30m/s*sin(25))=2900kg(9m/s)sin(α)+730kg(32.54m/s)sin(β) The...

Whats more basic - Newtons third law or conservation of momentum You can prove Newtons third law by conservation of momentum but you can also prove conservation of momentum by Newtons third law. What comes first?

Homework Statement Suppose we have done a conservation of momentum lab the smart pulley apparatus shown in the figure provided. With this apparatus we can time the motion of cart #1 very accurately. In the beginning cart #2 was stationary. We set cart #1 in motion by giving it a slight push...

Is conservation of momentum a fundamental thing? For example :- conservation of energy is basic, its fundamental, it has no answer of why it is conserved. Its just a rule of nature So in the same way, is conservation of momentum a rule of nature or does it have a deeper reason? And Newtons...

We've been discussing the principle of Conservation of Momentum lately in class and I've been wondering, the principle states that for two bodies: m1u1+m2u2= m1v1+m2v2 I understand that there are some rules which surround this principle but we haven't been shown them in full and I was...

Two blocks of mass m connected by a light string passing over a pulley. Say, one of the blocks is pushed downwards with a force F and it attains velocity v.So the other block moves upwards with the same speed v right? Total moementum = mv - mv = 0( because one is moving upwards and other...

Hello All, The following may be a simple problem. But, your thoughts will be very much appreciated. Homework Statement Let's use a gun with mass m1 and a bullet m2. The bullet is fired in the positive direction with speed v2, and the gun recoils in the negative direction with speed v1...

Homework Statement An space traveler is eating his lunch in his spaceship when he realizes he has drifted into the middle of the room and can not grab any of the walls. Stuck, floating without gravity to pull him to the floor, he comes up with an idea. He realizes that if he starts throwing...

Suppose we have two objects and we're only talking about rectilinear motion. Initially, one object has mass m and is moving at velocity V. The other has mass M and is standing still. Then they hit each other and suppose that all kinetic energy is conserved and they stick together and move at...

If object A and object B collide. Object A is going horizontally while object B is going up-diagonally. We find the momentum of object A to be 10 kg m/s while the momentum of B is 20 kgm/s. Does that mean that in the entire system after the collision there will have to be 10 kg m/s horizontally...

Homework Statement A 930 kg sports car collides into the rear end of a 2300 kg SUV stopped at a red light. The bumpers lock, the brakes are locked, and the two cars skid forward 2.9 m before stopping. The police officer, knowing that the coefficient of kinetic friction between tires and...

Homework Statement Tank (mass M) contains water (mass m). L is distance from centre of mass of container to pipe.(x) is noted as the direction to the right. Pipe is small compared to tank. Tank is sitting on a frictionless surface Open the tap, water flows out. After, where is the tank and...

Homework Statement Object 1 has a mass of 2.8 kg and is moving eastward with a velocity of 7.7 m/s. It collides with a stationary object. After the collision object 1 recoils with a velocity of -2.2 m/s What is the mass of object 2? Homework Equations As far as I know...

Homework Statement Object 1 has a mass of 2.8 kg and is moving eastward with a velocity of 7.7 m/s. It collides with a stationary object. After the collision object 1 recoils with a velocity of -2.2 m/s What is the mass of object 2?Homework Equations As far as I know: Conservation of...

From conservation of momentum and energy, it turns out that if two objects bump into each other and end up moving at the same speed, energy must have been lost. I know the formulas and calculations, but what physically happens at the contact site? Why cannot one object just push the other one...

Homework Statement Homework Equations m1v1i + m2v2i = m1v1f + m2v2f (Conservation of momentum) (1/2)m2*(v2i)^2 + (1/2)m1*(v1i)^2 = (1/2)m2*(v2f)^2 + (1/2)m1*(v1f)^2 (Conservation of energy)The Attempt at a Solution I separated the momentum into x and y components and got 2 equations I used the...

Does a collision that happens in water have a stronger impact than a collision on land?

Homework Statement a ball falls in a truck loaded with sand with velocity v having horizontal and vertical component. The angle under which it enters the truck is α, the mass of the ball is m of the track loaded with sand is M. What happens with the momentum after the collision? The...

Can someone explain this please. From what I understand momentum is often the more fundamental as it is spatially invariant, whereas energy is time invariant and as more real world cases fall into the former category momentum is often more fundamental. What is meant by spatial invariance...

Homework Statement A ball of mass m_1 travels along the x-axis in the positive direction with an initial speed of v_0. It collides with a ball of mass m_2 that is originally at rest. After the collision, the ball of mass m_1 has velocity {v_1}_{x}{\hat{x}}+{v_1}_{y}{\hat{y}} and the ball of...

Homework Statement In this exercise we used steel and glass balls to calculate and prove the conservation of momentum in elastic collisions. I had to prove how momentum is conserved through displacements vectors and right triangles. All that stuff is easy and I got it. The last question is...

A steel ball of mass moving with a velocity of 2.0 m/s [E], strikes a 1.2 kg copper ball initially moving 1.0m/s [W]. The collision is a glancing one, causing the steel ball to have a velocity of 1.5 m/s [W 30 degrees N] and the copper to move in the direction [E 47 degrees S]. Is the collision...

Homework Statement Two cars collide at right angle in the intersection of two icy roads. Car A has a mass of 1000 kg and car B 1400 kg. The cars become entangled and moved off together with a common velocity v’ in the direction indicated in figure QB4. If car A was traveling 10 m/s at the...

hi i was thinking about the photoelectric effect, that we discussed in school: we said that, when a photon enters, it has an energy and this energy is used for electron binding energy and kinetic energy. so far so good. but how is it possible, that the electron is emitted in the opposite...

Homework Statement The speed of a projectile is measured by shooting it into a sanbox hanging in 6.00 m long threads. The projectile has a mass of 12.0 g, and the sandbox has a mass of 3.00 kg. The projectile ends up laying still in the sandbox. Thus the sandbox and the projectile moves as...

Homework Statement Find the speed v of the rocket when the mass of the rocket = m. The rocket starts from rest at with mass M. Fuel is ejected at speed u relative to the rocket. Homework Equations m1v1 = m2v2 The Attempt at a Solution In the textbook, it starts off with a moving...

When you jump on a weighing scale the instant that you hit you're weight is higher than it would be if you were to gently step on on.Can someone give me a proper answer? I think its somehow related to conservation of momentum but i can't think of a proper answer. Also,suppose you two balls and...

Homework Statement The system shown above has a spring attached to two masses. Mass I is 3 times greater in mass than Mass II. The spring is initially stretched and let go to allow the two masses to approach each other. Which of the following is the same for both masses? a. speed b...

Homework Statement Block A with mass 13kg is moving right on a frictionless table. Block B with mass 1kg is moving left. Block B has a spring on its left side, the side that will hit Block A. THe question is: Which is the same for both after the collision? 1. speed 2. velocity 3...

Hello! As the title suggests I tried to use the photoelectric equation and convert it into conservation of momentum equation but something's not fitting in. We know that the initial momentum of the electron and the final momentum of the photon would be zero. Is there any other way...

Homework Statement 1. A moving object collides with a stationary object. (a) Is it possible for both objects to be at rest after the collision? If "yes," give an example. If "no," explain why not. (b) Is it possible for only one object to be at rest after the collision? If "yes," give an...

Gerald and Ashley stand face to face on some ice. They push off against each other and move apart from each other in opposite directions. Gerald moves with a velocity of 3m/s and Ashley moves with a velocity of 5m/s. If Gerald has a mass of 110 kg, what is Ashley's mass?

Homework Statement 2 balls hang from a modified Newtons Cradle, on of mass 80g, the other of mass 200g. Assuming gravity is 9.81ms^-2 ball A is pulled out so it reaches a height of 10cm then released. After impact ball 2 moves at a speed of 0.80ms^-1... calculate the velocity of sphere A...

If an object with mass m kg moves towards a wall with velocity u m/s, collides elastically with the wall and finally moves with a velocity –u m/s, then according to the equation of conservation of momentum: mu=-mu where the final momentum of the wall is negligible. This equation does not seem to...

There was a question in my textbook that howed a graph of momentum (a straight line because it is constant) and a graph of kinetic energy before and after a collision. After the collision the energy was less than the kinetic energy it stared out with. Doesn't that mean that speed has decreased...

Homework Statement A 1 Kg car moving at 2m/s collides elastically with a stationary car. The first car rebounds opposite to the original direction at 1m/s and the second car moves off in the original direction of the first car. A) What is the mass of the 2nd car B) What is the speed of...

Homework Statement mass of Fuzzy = 100.0kg mass of cart = 200.0kg Homework Equations Conservation of Momentum for 1D Motion Relative Velocity for 1D Motion The Attempt at a Solution Since everything is at rest at the beginning, the total momentum of the system is 0. So at the end, 0 =...

So I calculate the momentum of a body moving with a constant speed along a circular path with mass m, tangential velocity v and radius r. Its angular momentum is mvr.kk. Good. Now what if I calculate the angular momentum from a point on the path of the circle. A simple calculation shows that the...

Homework Statement I've been trying to solve this question for hours now, NEED HELP You are standing in a shop, holding an expensive vase of mass m. The vase accidentally slips from your hand and falls to the floor. It breaks into three pieces, two of mass 1/4m and one of mass 1/2m. The...

Homework Statement A 15 kg cart is moving east at 3.0 m/s when 10 kg of newspaper is vertically dropped into the cart. Find final veocity?[b]2. Homework Equations [/b m1v1i+m2v2i=m1v1f+m2v2f Kinematic eqs and trig will be necessary to find components for the 10kgnewspaper The Attempt at a...

Homework Statement A ball of mass 3m collides head-on with a initially stationary ball of mass m. No kinetic energy is transformed into heat, or sound. In what direction is the mass-3m ball moving after the collision, and how fast is it going compared to its original velocity?Homework...

Ok, I've been wondering about this question for many years and I don't know whether I just don't understand the basic concepts enough. If you have a rapidly-spinning neutron star that continues to collapse down to a singularity, what happens to the conservation of angular momentum from the...

Homework Statement A spaceship of mass 2.30×10^6kg is cruising at a speed of 5.40×10^6m/s when the antimatter reactor fails, blowing the ship into three pieces. One section, having a mass of 5.20×10^5kg, is blown straight backward with a speed of 2.20×10^6m/s. A second piece, with mass...

If a body of mass m and velocity u collides with another body of mass m which is stationary, and then the two bodies move off together, then conservation of momentum suggests that the since the combined mass is 2m, the new velocity will be 1/2 u. Total momentum before collision = mu + m0 =...