bola_mc._vx = 5;
bola_mc._vy = 5;

bola_mc.onEnterFrame = function() {
	this._x += this._vx;
	this._y += this._vy;
	
	if (this._x > 550 - this._height / 2) {
		this._x = 550 - this._height / 2;
		this._vx *= -1;
	}
	if (this._y > 400 - this._height / 2) {
		this._y = 400 - this._height / 2;
		this._vy *= -1;
	}
	if (this._x < 0 + this._height / 2) {
		this._x = 0 + this._height / 2;
		this._vx *= -1;
	}
	if (this._y < 0 + this._height / 2) {
		this._y = 0 + this._height / 2;
		this._vy *= -1;
	}
	
	if (Key.isDown(Key.UP)) {
		this._vy -= 10;
	}
	
	if (Key.isDown(Key.DOWN)) {
		this._vy += 10;
	}
	
	if (Key.isDown(Key.LEFT)) {
		this._vx -= 10;
	}
	
	if (Key.isDown(Key.RIGHT)) {
		this._vx += 10;
	}
	
	this._vy += 3;
	this._vx *= 0.98;
	this._vy *= 0.98;
}