Why wont this script detect collision? (Script error: OnCollisionEnter)

Questions & Answers
1

So I’m watching this tutorial and for my player to detect if he hit an obstacle or not, I would have to put in the code in the first picture, When I’m done saving the script and go back to Unity, it says “Script error: OnCollisionEnter” and it updates into the code in the second picture. Anyone know the problem and solution to this. Thank you.

Tutorial: How to make a Video Game in Unity - COLLISION (E05) - YouTube (4:00)

2

some times when script dont named with large letter on the start of all words it will do random errors like that