code: function computeVelocity(vel) {
           // apply fore if defined
           if (this.force.x) {
             vel.x += this.force.x * me.timer.tick;
           }
  
           if (this.force.y) {
             vel.y += this.force.y * me.timer.tick;
           } // apply friction
  
  
           if (this.friction.x || this.friction.y) {
             this.applyFriction(vel);
           } // apply gravity if defined
  
  
           if (this.gravity.y) {
             vel.x += this.gravity.x * this.mass * me.timer.tick;
           }
  
           if (this.gravity.y) {
             vel.y += this.gravity.y * this.mass * me.timer.tick; // check if falling / jumping
  
             this.falling = vel.y * Math.sign(this.gravity.y) > 0;
             this.jumping = this.falling ? false : this.jumping;
           } // cap velocity
  
  
           if (vel.y !== 0) {
             vel.y = me.Math.clamp(vel.y, -this.maxVel.y, this.maxVel.y);
           }
  
           if (vel.x !== 0) {
             vel.x = me.Math.clamp(vel.x, -this.maxVel.x, this.maxVel.x);
           }
         }
docs: compute the new velocity value
  @ignore