#physicsquestion which ball will exert a greater #force? #physics #physicsteacher #collisions

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I believe the sad one exerts more force on the table, since it saves little to no energy for rebounding. And the happy one would have a greater change in momentum because momentum is a vector, and its changing direction.

fourlefclover
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F =ma

m1 = m2
a = constant

Force exerted is the same for both.

Change in Momentum (p) = m (vi- vf)
Momentum is a vector so if we orient ourselves to take the downward direction of travel as negative,

Sad change in velocity is (-Vi - 0) as the ball comes to a complete stop.

Happy change in velocity is (-Vi - Vf)

In which case Force remains the same on both but the happy ball experiences the greater change in momentum.

nj
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Happy ball's velocity changes from +v to -v, which is a 2v difference (assuming perfect bounce, but anything bigger than 1v will do). Sad ball loses all of its momentum, so that is +v to 0, 1v change. Assuming they have identical mass; happy ball will have a greater momentum change. Now, lets assume impacts are momentary and we can simply the whole interaction into a simple rigid collision. Then, clearly happy ball must experience bigger force to experience bigger momentum change. By equal action-reaction principle, desk experiences the same force.

Now, for people concerned with energy, force does not necessarily mean energy. Happy ball retains all of its (kinetic)energy during the bounce while sad ball dissipates all of it as heat. You can closely look at work done during the bounce tonsee that for happy ball, table steal all its energy during the first half, then gives it all back during second half ( w = F x, F x are opposite direction in the first half)

Others might be concerned with conservation of total momentum. When we let go of the ball, earth + ball has some total momentum. Let's call it 0 datum. At every point in time as the ball is accelerated, total momentum is still unchanged, it is balanced by the earth (because the Earth falls towards the ball at a very very slow speed as well. As you can see, not very usefull. Of course, I ignored everything in the universe outside earth+ball.

dobacetr
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The happy ball exerts a greater force on the table because its change in momentum is greater than the sad ball. So the happy ball exerts greater force and greater change in momentum. The happy ball does it all.

anthonygonzales
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The one thing i can say for sure is that they did the Terminator theme. You're welcome.

MILOPETIT
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They both hit zero velocity on the table. So that means they both get an equal force pushed back on them by the table. Also, potential energy is the same at the beginning, so it’s impossible for one to suddenly have more force.

So equal force but happy has greater change of momentum since it not only stops but goes “negative” direction

These are just my guesses of course

michaelmanning
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The one that actually identifies as a ball.

yetiwookie
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Same the sad ball's lack of rebound is a result of the materials the ball is made from.l the interaction between the table and balls will he the same the equal and opposite reaction in the sad ball looks different due to differences in deformation of the balls.... I think

graemecowell
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*_Sad one puts its energy INTO the desk, and the other maintains it and uses it to bounce..?_*_ Am i wrong or..?_
🤔😳😆🤷🏼
#PleaseAdvise!

LBCB
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F=m.a, they both have the same mass, both subject to the same acceleration due to gravity, therefore they both exert the same force F.

DuaneDibbley-cp
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Bouncy changes momentum more the other is a dead blow hammer so it exerts more force on the table right

johnblackford
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i think sad ball at first because it had no conservation of energy so dumps all its energy in one go but once happy ball stops bouncing it will have used the same amount of energy over time. so sad ball to begin with after first touch to the table then happy ball after stops bouncing equals same energy. just a guess

MASSMAHEMMAKER
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"which one would exert a greater F and have a greater ∆P?"
Ok. When?!? At moment of impact? Or overall?
I think at moment of impact they have the same exerted F but Sad disipates the opposing resulting force from the table into heat quicker while Happy dissipates that opposing force into ∆P over a grater period of time (multiple bounces), thus overall energy is conserved, but the transformation of energy differs.
I'm verry curious for anyone to correct me if I'm wrong. Thaks!

marian-gabriel
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The sad one transfers more of its kinetic energy in a shorter span to the floor given its high plasticity so this makes me assume it 'might be the one with the greater force', tho I am a bit conflicted since energy transfer is not the same as force

And for the momentum, if momentum is the vector of mass-velocity, given that the mass doesn't change but the direction does I would say the happy ball is the one with the greater momentum change

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Same force different direction. Sad one greatest change of momentum

garyeast
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Force should be equal. Unless the added weight from sad ball is being measured? It's a new constant force if we are looking at it as a long term measurement and not instantaneous.

Happy ball moves from momentum in one direction through 0 to an opposite momentum almost instantaneously. It has a higher change.

overtlycriticaldork
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Probably the one that doesn't bounce, because it's not made from an elastic material, and even if the force itself isn't greater, the energy realesed will be, i.e. heat, friction etc.

joshneandertallclark
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Same mass, but the happy one pushes back up, so it has to push against the table and push towards it's stop point. Happy ball gives the most push downwards, right??

gpjens
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I think the sad ball will put more force on the table(floor) because all the energy is lost from the ball. The happy ball keeps a part of the energy .

jasper
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I'm guessing the happy one exerts more on the table

I would like feedback (:

eydum