This rock known as balanced rock sits on a thin spike of rock in a canyon in idaho. explain the that keep the rock balanced on its tiny pedestal

Now, suppose you have a more common figure, like a square, and you want to balance it over a pencil for example.

When you put the square over the pencil, you want that the point where the square touches the pencil is right in the middle of one of the faces of the square. This is because, in this situation, you know that the mass is evenly distributed over all sides now, and none side of the square is pulling down with more force than another side.

Now, this is the same with this rock, the mass is evenly distributed around the contact point, so no side has more force downwards than another side, then all the forces are canceled, and if there are no forces acting on the rock, it will remain in place.

air exerts forces on falling objects near earth’s surface.

explanation:

the term 'free falls' refer to object that are falling towards the earth, in a situation in which gravity is the only force acting on the object.

for an object in free fall, the acceleration is constant (g, the gravitational acceleration), and so the velocity of the object constantly increases.

for objects near earth's surface, there is always another force acting on the object: the resistance due to the air. this force is opposed to the direction of fall of the object, and it is proportional to the velocity of the object, so as the object falls down, this force increases up to a point when it balances the force of gravity, and the object continues its motion at constant velocity (called terminal velocity). since in this case gravity is not the only force acting on the object, we are not in a situation of free fall.