# I want to know the trig maths for calculating the collision normal after collision

**URL:** <https://discourse.processing.org/t/i-want-to-know-the-trig-maths-for-calculating-the-collision-normal-after-collision/22017>\
**Category:** Coding Questions\
**Created:** [June 20, 2020, 6:09am UTC](https://discourse.processing.org/t/i-want-to-know-the-trig-maths-for-calculating-the-collision-normal-after-collision/22017 "2020-06-20T06:09:16Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![Why\_I\_Use\_Processing](https://yyz2.discourse-cdn.com/flex036/user_avatar/discourse.processing.org/why_i_use_processing/32/9558_2.png) [@Why\_I\_Use\_Processing](https://discourse.processing.org/u/Why_I_Use_Processing)\
**Post date:** [June 20, 2020, 6:09am UTC](https://discourse.processing.org/t/i-want-to-know-the-trig-maths-for-calculating-the-collision-normal-after-collision/22017/1 "2020-06-20T06:09:17Z")

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I want that car shown below in the image to bounce off the tribune after collision.  
I already made the collision detections work, I just want to apply some physics after collision(collision normal, velocity component, etc…)

Thanks in advance…

 ![Screenshot_2020-06-20-11-36-18-330_com.calsignlabs.apde.sketchpreview](https://canada1.discourse-cdn.com/flex036/uploads/processingfoundation1/original/2X/6/6f266b19a8e024cd71f38f5e8b8e86d24c374cfb.jpeg)

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**Author:** ![Mesalcode](https://yyz2.discourse-cdn.com/flex036/user_avatar/discourse.processing.org/mesalcode/32/9284_2.png) [@Mesalcode](https://discourse.processing.org/u/Mesalcode)\
**Post date:** [June 20, 2020, 2:43pm UTC](https://discourse.processing.org/t/i-want-to-know-the-trig-maths-for-calculating-the-collision-normal-after-collision/22017/2 "2020-06-20T14:43:32Z")

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This is not a code writing service. Try something yourself and we’ll tell you why it does not work, but not this way.

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**Author:** ![quark](https://yyz2.discourse-cdn.com/flex036/user_avatar/discourse.processing.org/quark/32/26_2.png) [@quark](https://discourse.processing.org/u/quark)\
**Post date:** [June 20, 2020, 2:59pm UTC](https://discourse.processing.org/t/i-want-to-know-the-trig-maths-for-calculating-the-collision-normal-after-collision/22017/3 "2020-06-20T14:59:57Z")

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What is the “tribune”?

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**Author:** ![noel](https://yyz2.discourse-cdn.com/flex036/user_avatar/discourse.processing.org/noel/32/213_2.png) [@noel](https://discourse.processing.org/u/noel)\
**Post date:** [June 20, 2020, 6:42pm UTC](https://discourse.processing.org/t/i-want-to-know-the-trig-maths-for-calculating-the-collision-normal-after-collision/22017/4 "2020-06-20T18:42:24Z")

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You could start studying [this](https://processing.org/examples/circlecollision.html) example.