10899 - Billiard again

All about problems in Volume 108. If there is a thread about your problem, please use it. If not, create one with its number in the subject.

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artem
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10899 - Billiard again

Post by artem » Wed Aug 31, 2005 10:05 pm

Please help me.
I have some questions about this problem.

Code: Select all

1 Whats means this sentence "Before the first bounce, the ball increases its distance from the lower left corner of the table."
2 Initinally ball have coordinantes (a/2,b/2) (i think this coord of middle of table)?
3 
(0,b)                              (a,b)
----------------------------------
|           90 degrees           |
|                 |              |
|                 |              |
|   180 degrees -- -- 0 degrees  |
|                 |              |
|                 |              |
|            270 degrees         |
----------------------------------
(0,0)                              (a,0)

This image is right?

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Martin Macko
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Re: Problem 10899

Post by Martin Macko » Wed Aug 31, 2005 10:33 pm

artem wrote:2 Initinally ball have coordinantes (a/2,b/2) (i think this coord of middle of table)?
Yes. :D (Watch the division if a or b is odd.)
artem wrote:3

Code: Select all

(0,b)                              (a,b)
----------------------------------
|           90 degrees           |
|                 |              |
|                 |              |
|   180 degrees -- -- 0 degrees  |
|                 |              |
|                 |              |
|            270 degrees         |
----------------------------------
(0,0)                              (a,0)
This image is right?
Yes, it is :wink:
artem wrote:1 Whats means this sentence "Before the first bounce, the ball increases its distance from the lower left corner of the table."
As the initial angle is between 0 and 90 degrees, the ball will go up and/or right from the middle of the table. Thus increasing its distance from lower left (0,0) corner.

artem
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Posts: 17
Joined: Thu Jun 09, 2005 5:01 pm

Post by artem » Wed Aug 31, 2005 11:35 pm

Thank you very much Martin, i found my logical mistake (i think that length of path of ball is s*v, but i mistaken, length of path of ball is s*v/2) and got AC.

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