Cricket physics, a basic simulation

3
votes

I am coding a simulation of a cricket player throwing a ball and I have come to the part where the player throws the ball. I don't think my simulation of the ball is very accurate though and I am not quite sure why (no idea what to be looking for in physics). What I have so far is something similar to this, the arm has a rotation speed and the ball is released at a certain point. So I approached this using a vector from the arm to the ball, I figured the direction the ball should travel in the direction of the right normal. So this is what I have for the direction.

throwSpeedHorz = -1*sin(bowlerArmRotation * (3.14159/180)); // * rotationSpeed
throwSpeedVert = cos(bowlerArmRotation * (3.14159/180)); // * rotationSpeed

The problem I have is how do I use the speed of the arm with this to get the total speed for each. I have tried multiplying it by the speed of rotation which gave a way too high number for the speed. If someone can point me in the right direction it will be greatly appreciated.

1
mathphysicssimulation
What is bowlerArmRotation supposed to contain? And can you give an example of a value it would have? - Jonathan M
The rotation speed contains how much the rotation will change in the next frame, so it speeds up over time. Like an acceleration value, it is added to bowlerArmRotation each frame until the ball is thrown - Danny Birch
What is the length of the bowler arm, and what is its rotational speed in cycles per second? - Jonathan M
Its roughly around 4.5 cycles a second and the length of the ball from the centre of the arm is 4 - Danny Birch
If the arm is 4 (feet?), the release speed of the ball would then be 4*2*PI*4.5 feet per second, or roughly 113 feet per second. If it's pixels instead of feet, it's just 113 pixels/second. You take the distance unit (feet or pixels) from the arm, and the time unit (seconds) from the rotational speed. - Jonathan M

1 Answers

2
votes

Speed is usually given in rotations per second, so the speed of the tip of bowlers "arm" is given by

speed = rotationSpeed * 2 * PI * bowlerArmLength

(or more exactly the distance of the ball to the rotation axis). You can then extract horizontal and vertical components as described in your question.