let acceleration;

let a=0;

let isAccelerating = false;

let counter;

​

function setup() {

  createCanvas(400, 400);

  circle = new Circle(width / 2, height / 2, 30,a);

}

​

function draw() {

  background(220);

//   if (isAccelerating == true) {

//      a=10;

//   // } else {

//   //   a=a*-0.1;

  }

  circle.update();

  circle.display();

  // Reset the circle's position if it goes below the canvas height

  if (circle.position.y > height) {

    circle.position.y = 0;

  }

}

​

function keyPressed() {

  if (keyCode === DOWN_ARROW) {

    a=10;

//     isAccelerating = true;

  }

}

​

// function keyReleased() {

//   if (keyCode === DOWN_ARROW) {

//     isAccelerating = false;

//   }

// }

​

class Circle {

  constructor(x, y, r,a) {

    this.position = createVector(x, y);

    this.velocity = createVector(0, 0);

    this.acceleration = createVector(a, a);

    this.radius = r;

  }

​

  update() {

    this.velocity.add(this.acceleration);

    this.position.add(this.velocity);

  }

  display() {

    ellipse(this.position.x, this.position.y, this.radius * 2);

  }

​

  // accelerate(a) {

  //   this.acceleration.y += a;

  // }

}

​