// F = -kx

// does not use any trigonometry!

​

let p;

​

let A = 100;

​

function setup() {

  createCanvas(400, 400);

​

  p = new Particle(A, 0);

}

​

function draw() {

  background(220);

​

  translate(width / 2, height / 2);

  fill(255)

  line(0, 0, p.pos.x, p.pos.y)

  p.update()

  p.draw();

  let k = 0.01

  let f = p5.Vector.mult(p.pos, -k)

  p.applyForce(f)

  // to calculate the frequency of oscillation:

  // Initial conditions:

  // A = 100, m = 1, k = 0.01

  // ω = √(k/m)

  let omega = sqrt(k/p.m)

  fill(0)

  ellipse(A*cos(omega*frameCount), 100, 16)

  // artificial shm by setting position

}

​

​