Improve this answer. Brandon Enright Brandon Enright Can you back this up with some math? This answer is so very wrong. Momentum and energy are conserved quantities in classical mechanics. There's a lot more to energy than just kinetic energy, which means that kinetic energy is not necessarily a conserved quantity.
I also mentioned other manifestations of energy in the last sentence. With that said, do you think the answer is technically wrong or just an incomplete simplification? Show 3 more comments. This answer doesn't really address that, it just restates the unchallenged premise of the question which is that momentum is of course conserved. You may merge it with my main account. I leave it to you to contact the SE team. Show 6 more comments. Eric Angle Eric Angle 2, 16 16 silver badges 14 14 bronze badges.
Doesnt a faster moving particle have more momentum too? Community Bot 1. David Rose David Rose 5 5 silver badges 5 5 bronze badges. DWin DWin 4 4 silver badges 9 9 bronze badges. This is why momentum is always conserved but kinetic energy need not be conserved. It is often frown upon to post nearly identical answers to similar posts. This is a question-and-answer site for people with specific conceptual questions about physics and their answers. I hope that you're able to stick around and contribute productively to our task of answering discussion questions.
Your opening sentence also communicates a conversational feel among answers, as in, say, a Facebook thread--I prefer to treat Stack answers as independent cells. Finally your writing may strengthen, becoming more persuasive, if you lean less on insubstantial verbs like "is" in your answers. Welcome again, and happy answering! We know that the momentum will still remain conserved. Vishnu JK 10 10 silver badges 18 18 bronze badges. Kartik Kartik 1 1 1 bronze badge.
Now this is perfectly a math problem. It's not constant, right? Marco Ocram Marco Ocram Loz J. Loz 6 6 bronze badges. John Alexiou John Alexiou With energy not a vector , you can convert kinetic energy of the objects into kinetic energy of the molecules in any direction heat. With momentum though, the vector direction is conserved so even though the molecules gain momentum from their movement, the sum of all molecule momentums is still exactly the net momentum in the direction the object was traveling in the first place.
Mario Mario 1. Total mechanical energy is only reduced when there are non conservative forces involved in the collision. My statement is correct. Conor Cosnett Conor Cosnett 7 7 bronze badges. But you haven't explained why the observed outcomes that fail to conserve both are those than conserve momentum and not those that conserve bulk kinetic energy.
Featured on Meta. Now live: A fully responsive profile. Linked 7. See more linked questions. In a low speed collision, the kinetic energy is small enough that the bumper can deform and then bounce back, transferring all the energy directly back into motion. Almost no energy is converted into heat, noise, or damage to the body of the car, as it would in an inelastic collision.
However, car bumpers are often made to collapse if the speed is high enough, and not use the benefits of an elastic collision. The rational is that if you are going to collide with something at a high speed, it is better to allow the kinetic energy to crumple the bumper in an inelastic collision than let the bumper shake you around as your car bounces in an elastic collision.
Making their bumpers this way benefits the car companies: they get to sell you a new bumper, and you can't sue them for whiplash. Clearly, the motor had to work to get the stone spinning.
This work went into heat, light, sound, vibration, and considerable rotational kinetic energy. Grindstone : The motor works in spinning the grindstone, giving it rotational kinetic energy. That energy is then converted to heat, light, sound, and vibration. Credit: U. Work must be done to rotate objects such as grindstones or merry-go-rounds. The simplest rotational situation is one in which the net force is exerted perpendicular to the radius of a disc and remains perpendicular as the disc starts to rotate.
The before- and after-collision velocities and momentum are shown in the data tables. In the collision between the truck and the car, total system momentum is conserved.
The total system momentum is conserved. An analysis of the kinetic energy of the two objects reveals that the total system kinetic energy before the collision is Joules J for the truck plus 0 J for the car. After the collision, the total system kinetic energy is Joules J for the truck and J for the car.
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