CODEWITHSUNDEEP
c#unity-game-enginephysicsgame-physics
AlanF
AlanF

Reputation: 1601

Calculating time based on velocity, distance and radius of two balls

How would I get the time needed for two balls to collide when the following are all constants

initial position of both balls

initial velocity of both balls

radius of the both balls

I am doing out a few examples in Unity 3D using c# for the code. I am not asking for the code, I just would like to know what steps to take to do this (physics wise).

Any help is appreciated

Upvotes: 1

Views: 664

Answers (1)

mdg16
mdg16

Reputation: 66

Assume constants for each ball are distance (d1), velocity (v1), radius (r1), start position (p1)... etc. Also assume that the balls move in a 1D world along a tape measure.

distance = velocity * time

Distance between the balls accounting for their size: distance = p1 - p2 - (r1 + r2)

Velocity is the combined velocities of the balls (V): V = v1+v2 ** note that direction matters. If they are going towards one another, they sum. Away from one another, they subtract.

So now... V * t = p1 - p2 - (r1 + r2)

time to collision is: t = [p1 - p2 - (r1 + r2)] / V

Upvotes: 3

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