[Vuejs]-Error implementing projectile motion to ball

This works but with the amendments below. Hope that helps.

https://jsfiddle.net/ferjb716/

I do not know how this part is supposed to work so I simplified it.
I’d be interested in how to do it with the original values.

  let newPosY =
          ball.posY + ball.velY - 0.5 * this.gravity * Math.pow(ball.time, 2);

Simplifying it to

 let newPosY = ball.posY + ball.velY * ball.time

worked

Also these look like errors

Errors

from: velX

if (newPosY <= ball.radius) { //collision on top
      // ball.velY = Math.abs(ball.velY * 0.9);
      ball.velY = -ball.velX * 0.9;
    }

if (newPosY >= this.screenHeight - ball.radius) { //collision on bottom
  // ball.velY = -Math.abs(ball.velY * 0.9);          
  ball.velY = -ball.velX * 0.9;
}

changed to velY

 if (newPosY <= ball.radius) { //colision on top
          // ball.velY = Math.abs(ball.velY * 0.9);
          ball.velY = -ball.velY * 0.9;  //correction
        }

 if (newPosY >= this.screenHeight - ball.radius) { //colition on bottom
          // ball.velY = -Math.abs(ball.velY * 0.9);          
          ball.velY = -ball.velY * 0.9;   //correction
        }