How to move ball speedily on the screen using box2d in libGDX?

public class Box2DDemo implements ApplicationListener {

private SpriteBatch batch;
private TextureRegion texture;
private World world;
private Body groundDownBody, groundUpBody, groundLeftBody, groundRightBody,
        ballBody;
private BodyDef groundBodyDef1, groundBodyDef2, groundBodyDef3,
        groundBodyDef4, ballBodyDef;
private PolygonShape groundDownPoly, groundUpPoly, groundLeftPoly,
        groundRightPoly;
private CircleShape ballPoly;
private Sprite sprite;
private FixtureDef fixtureDef;
private Vector2 ballPosition;
private Box2DDebugRenderer renderer;
Vector2 vector2;

@Override
public void create() {

    texture = new TextureRegion(new Texture(
            Gdx.files.internal("img/red_ring.png")));
    sprite = new Sprite(texture);
    sprite.setOrigin(sprite.getWidth() / 2, sprite.getHeight() / 2);
    batch = new SpriteBatch();

    world = new World(new Vector2(0.0f, -10.0f), false);

    groundBodyDef1 = new BodyDef();
    groundBodyDef1.type = BodyType.StaticBody;
    groundBodyDef1.position.x = 0.0f;
    groundBodyDef1.position.y = 0.0f;
    groundDownBody = world.createBody(groundBodyDef1);

    groundBodyDef2 = new BodyDef();
    groundBodyDef2.type = BodyType.StaticBody;
    groundBodyDef2.position.x = 0f;
    groundBodyDef2.position.y = Gdx.graphics.getHeight();
    groundUpBody = world.createBody(groundBodyDef2);

    groundBodyDef3 = new BodyDef();
    groundBodyDef3.type = BodyType.StaticBody;
    groundBodyDef3.position.x = 0f;
    groundBodyDef3.position.y = 0f;
    groundLeftBody = world.createBody(groundBodyDef3);

    groundBodyDef4 = new BodyDef();
    groundBodyDef4.type = BodyType.StaticBody;
    groundBodyDef4.position.x = Gdx.graphics.getWidth();
    groundBodyDef4.position.y = 0f;
    groundRightBody = world.createBody(groundBodyDef4);

    groundDownPoly = new PolygonShape();
    groundDownPoly.setAsBox(480.0f, 10f);

    fixtureDef = new FixtureDef();
    fixtureDef.density = 0f;
    fixtureDef.restitution = 1f;
    fixtureDef.friction = 0f;
    fixtureDef.shape = groundDownPoly;

    fixtureDef.filter.groupIndex = 0;

    groundDownBody.createFixture(fixtureDef);

    groundUpPoly = new PolygonShape();
    groundUpPoly.setAsBox(480.0f, 10f);

    fixtureDef = new FixtureDef();
    fixtureDef.friction = 0f;
    fixtureDef.restitution = 0f;
    fixtureDef.density = 0f;
    fixtureDef.shape = groundUpPoly;
    fixtureDef.filter.groupIndex = 0;

    groundUpBody.createFixture(fixtureDef);

    groundLeftPoly = new PolygonShape();
    groundLeftPoly.setAsBox(10f, 320f);

    fixtureDef = new FixtureDef();
    fixtureDef.friction = 0f;
    fixtureDef.restitution = 0f;
    fixtureDef.density = 0f;
    fixtureDef.shape = groundLeftPoly;
    fixtureDef.filter.groupIndex = 0;

    groundLeftBody.createFixture(fixtureDef);

    groundRightPoly = new PolygonShape();
    groundRightPoly.setAsBox(10f, 320f);

    fixtureDef = new FixtureDef();

    fixtureDef.friction = 0f;
    fixtureDef.restitution = 0f;
    fixtureDef.density = 0f;
    fixtureDef.shape = groundRightPoly;
    fixtureDef.filter.groupIndex = 0;

    groundRightBody.createFixture(fixtureDef);

    ballPoly = new CircleShape();
    ballPoly.setRadius(16f);

    fixtureDef = new FixtureDef();
    fixtureDef.shape = ballPoly;
    fixtureDef.density = 1f;
    fixtureDef.friction = 1f;
    fixtureDef.restitution = 1f;

    ballBodyDef = new BodyDef();
    ballBodyDef.type = BodyType.DynamicBody;
    ballBodyDef.position.x = (int) 200;
    ballBodyDef.position.y = (int) 200;

    ballBody = world.createBody(ballBodyDef);
    // ballBody.setLinearVelocity(200f, 200f);
    // ballBody.applyLinearImpulse(new Vector2(250f, 250f),
    // ballBody.getLocalCenter());
    ballBody.createFixture(fixtureDef);

    renderer = new Box2DDebugRenderer(true, false, false);

}

@Override
public void dispose() {
    ballPoly.dispose();
    groundLeftPoly.dispose();
    groundUpPoly.dispose();
    groundDownPoly.dispose();
    groundRightPoly.dispose();
    world.destroyBody(ballBody);
    world.dispose();
}

@Override
public void pause() {
}

@Override
public void render() {

    world.step(1f/30f, 3, 3);

    Gdx.gl.glClearColor(1f, 1f, 1f, 1f);
    Gdx.gl.glClear(GL10.GL_COLOR_BUFFER_BIT);

    batch.begin();
    vector2 = ballBody.getLinearVelocity();

    System.out.println("X=" + vector2.x + " Y=" + vector2.y);

    ballPosition = ballBody.getPosition();
    renderer.render(world,batch.getProjectionMatrix());

    // int preX = (int) (vector2.x / Math.abs(vector2.x));
    // int preY = (int) (vector2.y / Math.abs(vector2.y));
    //
    // if (Math.abs(vector2.x) == 0.0f)
    // ballBody1.setLinearVelocity(1.4142137f, vector2.y);
    // else if (Math.abs(vector2.x) < 1.4142137f)
    // ballBody1.setLinearVelocity(preX * 5, vector2.y);
    //
    // if (Math.abs(vector2.y) == 0.0f)
    // ballBody1.setLinearVelocity(vector2.x, 1.4142137f);
    // else if (Math.abs(vector2.y) < 1.4142137f)
    // ballBody1.setLinearVelocity(vector2.x, preY * 5);

    batch.draw(sprite, (ballPosition.x - (texture.getRegionWidth() / 2)),
            (ballPosition.y - (texture.getRegionHeight() / 2)));

    batch.end();
}

@Override
public void resize(int arg0, int arg1) {
}

@Override
public void resume() {
}

}

I implement above code but I can not achieve higher moving speed of the ball