Objects moving on a plane












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Object 1 starting at point (0,0) on the coordinate plane moves to right at 1 unit per second. Another object (object 2) starts at (x,y), moving half the distance to object 1 each second (following a curved path). If Object 2 is within 1 unit of Object 1, then they collide.



(1) Prove that they collide if and only if $x≥0$



(2) Find (and prove) what the maximum value of $y/x+y$ is if they do indeed collide.



I tried to solve (1) so far, without much luck. I tried powers of 2 and starting object 2 on the y axis. I got a nasty equation, and that was just for one point.



Object 1 moves first, so the movement of object 2 is half the distance to the position of object 1 at the end of the second, but the movement of object 2 is considered instantaneous










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    $begingroup$


    Object 1 starting at point (0,0) on the coordinate plane moves to right at 1 unit per second. Another object (object 2) starts at (x,y), moving half the distance to object 1 each second (following a curved path). If Object 2 is within 1 unit of Object 1, then they collide.



    (1) Prove that they collide if and only if $x≥0$



    (2) Find (and prove) what the maximum value of $y/x+y$ is if they do indeed collide.



    I tried to solve (1) so far, without much luck. I tried powers of 2 and starting object 2 on the y axis. I got a nasty equation, and that was just for one point.



    Object 1 moves first, so the movement of object 2 is half the distance to the position of object 1 at the end of the second, but the movement of object 2 is considered instantaneous










    share|cite|improve this question









    $endgroup$















      0












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      0





      $begingroup$


      Object 1 starting at point (0,0) on the coordinate plane moves to right at 1 unit per second. Another object (object 2) starts at (x,y), moving half the distance to object 1 each second (following a curved path). If Object 2 is within 1 unit of Object 1, then they collide.



      (1) Prove that they collide if and only if $x≥0$



      (2) Find (and prove) what the maximum value of $y/x+y$ is if they do indeed collide.



      I tried to solve (1) so far, without much luck. I tried powers of 2 and starting object 2 on the y axis. I got a nasty equation, and that was just for one point.



      Object 1 moves first, so the movement of object 2 is half the distance to the position of object 1 at the end of the second, but the movement of object 2 is considered instantaneous










      share|cite|improve this question









      $endgroup$




      Object 1 starting at point (0,0) on the coordinate plane moves to right at 1 unit per second. Another object (object 2) starts at (x,y), moving half the distance to object 1 each second (following a curved path). If Object 2 is within 1 unit of Object 1, then they collide.



      (1) Prove that they collide if and only if $x≥0$



      (2) Find (and prove) what the maximum value of $y/x+y$ is if they do indeed collide.



      I tried to solve (1) so far, without much luck. I tried powers of 2 and starting object 2 on the y axis. I got a nasty equation, and that was just for one point.



      Object 1 moves first, so the movement of object 2 is half the distance to the position of object 1 at the end of the second, but the movement of object 2 is considered instantaneous







      algebra-precalculus functions graphing-functions algorithmic-game-theory






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      asked Jan 22 at 0:23









      mathboy1296mathboy1296

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          I'm afraid that (1) is not true.



          Assume it is true. Then if $x<0$ the object never collide.
          Consider now the situation $x=0$, $y=1000$. the objects will collide. After one second object 2 is a position $(0.5,500)$ and object one at $(1,0)$. Which is exactly the same situation as $x=-0.5$ and $y=500$ hence the object will not collide. Contradiction.






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            1 Answer
            1






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            0












            $begingroup$

            I'm afraid that (1) is not true.



            Assume it is true. Then if $x<0$ the object never collide.
            Consider now the situation $x=0$, $y=1000$. the objects will collide. After one second object 2 is a position $(0.5,500)$ and object one at $(1,0)$. Which is exactly the same situation as $x=-0.5$ and $y=500$ hence the object will not collide. Contradiction.






            share|cite|improve this answer









            $endgroup$


















              0












              $begingroup$

              I'm afraid that (1) is not true.



              Assume it is true. Then if $x<0$ the object never collide.
              Consider now the situation $x=0$, $y=1000$. the objects will collide. After one second object 2 is a position $(0.5,500)$ and object one at $(1,0)$. Which is exactly the same situation as $x=-0.5$ and $y=500$ hence the object will not collide. Contradiction.






              share|cite|improve this answer









              $endgroup$
















                0












                0








                0





                $begingroup$

                I'm afraid that (1) is not true.



                Assume it is true. Then if $x<0$ the object never collide.
                Consider now the situation $x=0$, $y=1000$. the objects will collide. After one second object 2 is a position $(0.5,500)$ and object one at $(1,0)$. Which is exactly the same situation as $x=-0.5$ and $y=500$ hence the object will not collide. Contradiction.






                share|cite|improve this answer









                $endgroup$



                I'm afraid that (1) is not true.



                Assume it is true. Then if $x<0$ the object never collide.
                Consider now the situation $x=0$, $y=1000$. the objects will collide. After one second object 2 is a position $(0.5,500)$ and object one at $(1,0)$. Which is exactly the same situation as $x=-0.5$ and $y=500$ hence the object will not collide. Contradiction.







                share|cite|improve this answer












                share|cite|improve this answer



                share|cite|improve this answer










                answered Jan 23 at 10:33









                wecewece

                2,3721923




                2,3721923






























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