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M2 collision problem

Two small smooth balls A anb B of equal radius and mass 4kg and 5kg respectively lie at rest on a smooth horizontal floor.Ball A is projected with speed u and collides with ball B.following this collision ball B then strikes a smooth vertical wall normally. After rebounding from the wall, ball B again collides with ball A. Given that ball B is brought to rest to rest by this second collision with A.

Show 2e^3-3e^2-3e+2 = 0 , e is the coefficient of restitution between the two balls and between ball B and the wall.
Original post by lovelypippy
Two small smooth balls A anb B of equal radius and mass 4kg and 5kg respectively lie at rest on a smooth horizontal floor.Ball A is projected with speed u and collides with ball B.following this collision ball B then strikes a smooth vertical wall normally. After rebounding from the wall, ball B again collides with ball A. Given that ball B is brought to rest to rest by this second collision with A.

Show 2e^3-3e^2-3e+2 = 0 , e is the coefficient of restitution between the two balls and between ball B and the wall.


This is really an exercise in algebra, as well as understanding the momentum and restitution equations.

After the first collision, you should have:

vA=u9(4−5e)v_A=\frac{u}{9}(4-5e)

vB=4u9(1+e)v_B=\frac{4u}{9}(1+e)

Post working if you're not getting those intermediate results.

For the final equation, I get something slightly different, so probably made a slip somewhere.

And post your working for the final equation if you'd like someone to check it.

Edit: Found the slip, and I agree with their equation now.
(edited 12 years ago)
Original post by Lahiru7
...


Please see the forum guidlines - sticky at top of forum -, particularly with regard to full solutions.
Reply 3
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Lahiru7
3
so what do u mean
is it wrong what I have done?
I proved that final answer
Reply 4
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Notnek
21
Original post by Lahiru7
so what do u mean
is it wrong what I have done?
I proved that final answer

Posting full solutions is against the rules of the maths forum so I have removed your post.

Please read though the posting guidelines. Thanks.
(edited 6 years ago)
Reply 5
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Lahiru7
3
ohh okay I'm sorry I didn't know
Reply 6
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Lahiru7
3
but I have seen so many answers for questions what about them?
What is the point of not posting correct answers
Then if someone needs to know about the answer what are u gonna do?
without full solutions what's the point?????
Reply 7
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Notnek
21
Original post by Lahiru7
but I have seen so many answers for questions what about them?
What is the point of not posting correct answers
Then if someone needs to know about the answer what are u gonna do?
without full solutions what's the point?????

Please read the answering questions guidelines if you haven't already.

The TSR maths forum is a teaching/understanding forum as opposed to a 'do my homework' forum. There are plenty of other places online where you can receive a full solution to a maths problem. If you go to your teacher for help with a maths problem, they would guide you to the solution instead of giving you the solution straight away and a similar thing happens here.

The majority of full solutions that are noticed by the Support Team will be removed. There may be some that go unnoticed but they are still against the rules.
Reply 8
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davros
16
Original post by Notnek
Please read the answering questions guidelines if you haven't already.



The majority of full solutions that are noticed by the Support Team will be removed. There may be some that go unnoticed but they are still against the rules.


This also appears to be a six-year-old thread that has been resurrected, and should probably be closed :smile:
Reply 9
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Notnek
21
Original post by davros
This also appears to be a six-year-old thread that has been resurrected, and should probably be closed :smile:

Thanks, I didn't notice that :smile:

Thread closed.

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