Penrith High reaches + 9 g force in Lab.

Actually it was just swirling a marble in a mop bucket.

The bucket wall was 84 degrees. g x 1/cos(84) = 9.5 g.

Students were asked to calculate the mass required to cause this acceleration at 15 cm in the center of the bucket.

The difference between the bucket and gravitation is that the bucket applies a force at the point of contact of the marble and force pushes and stress through out the marble, where as a gravitational field would tug uniformly throughout the marble. Gravitation gently accelerates the whole marble.

If you were in the marble, in the bucket you would be crushed to death, were as in the gravitational field as the force is spread evenly through out your body you would feel "Weightless". This is also why comets are not crushed as they swing near the Sun.

I am always looking for this explanation in Textbook, as without it it is most confusing.