I used the collision physics (i.e. Box2d, Physics Body Editor) and implemented onto the java code. I'm trying to make the fall speed higher according to the examples:

• It falls slower if light object (i.e. feather).
• It falls faster depending on the object (i.e. pebble, rock, car).

I decided to double its falling speed for more excitement. I tried adding the mass but the speed of falling is constant instead of gaining more speed. check my code that something I put under input processor's touchUp() return method under same roof of the class that implements InputProcessor and Screen:

@Override
public boolean touchUp(int screenX, int screenY, int pointer, int button) 
{
    // TODO Touch Up Event

    if(is_Next_Fruit_Touched)
    {
        BodyEditorLoader Fruit_Loader = new BodyEditorLoader(Gdx.files.internal("Shape_Physics/Fruity Physics.json"));

        Fruit_BD.type = BodyType.DynamicBody;
        Fruit_BD.position.set(x, y);

        FixtureDef Fruit_FD = new FixtureDef(); // --> Allows you to make the object's physics.
        Fruit_FD.density = 1.0f;
        Fruit_FD.friction = 0.7f;
        Fruit_FD.restitution = 0.2f;

        MassData mass = new MassData();
        mass.mass = 5f;

        Fruit_Body[n] = world.createBody(Fruit_BD);
        Fruit_Body[n].setActive(true); // --> Let your dragon fall.
        Fruit_Body[n].setMassData(mass);
        Fruit_Body[n].setGravityScale(1.0f);

        System.out.println("Eggs... " + n);

        Fruit_Loader.attachFixture(Fruit_Body[n], Body, Fruit_FD, Fruit_IMG.getWidth());
        Fruit_Origin = Fruit_Loader.getOrigin(Body, Fruit_IMG.getWidth()).cpy();

        is_Next_Fruit_Touched = false;
        up = y;
        Gdx.app.log("Initial Y-coordinate", "Y at " + up);

        //Once it's touched, the next fruit will set to drag.
        if(n < 50)
        {
            n++;

        }else{

            System.exit(0);

        }
    }

    return true;
}

And take note, at show() method , the view size from the camera is at 720x1280:

    camera_1 = new OrthographicCamera();
    camera_1.viewportHeight = 1280;
    camera_1.viewportWidth = 720;
    camera_1.position.set(camera_1.viewportWidth * 0.5f, camera_1.viewportHeight * 0.5f, 0f);
    camera_1.update();

I know it's a good idea to add weight to make the falling object falls faster once I released the finger from the touchUp() after I picked the object from the upper right of the screen but the speed remains either constant or slow. How can I solve this? Can you help?