Theory of Resting Force

While recently brushing up on my knowledge of Physics, I began reading a book called, “Merrill Physics, Principles and Problems, ©1995 by Glencoe/ McGraw-Hill. After reading page 88 on “Newton’s Laws of Motion”, I came to a statement that made me pause and question Isaac Newton’s theory of Force as it relates to motion. In the book, it explains that force is a push or pull and that when you place a jacket on a hook, the hook pushes up on the jacket and the jacket pushes down on the hook. It says this is what happens when two forces touch each other. I disagree.

In the first paragraph, it states that the hook pulls upward on the jacket. To me this sounds ridiculous. I thought about it for some time and tried to justify Newton’s theory by explaining that maybe he was thinking that the Earth’s rotation was trying to sling the hook upward as the jacket fell onto the hook. But this does not make sense, because the gravitational pull on the hook is NOT the weakest force as the book proclaims. Otherwise, the rotation of the Earth would be able to sling the hook into outer space. Oops! There goes the theory that gravity is the weakest force! It must be very strong to withstand the slinging motion of the revolutions both around the Sun and Earth’s rotations at the same time.

 

My Theory of Resting Force is that the hook is stationary and a stable or constant force as it relates to the position on Earth because it is a permanent fixture of the house which is a grounded object (gravitational) to the Earth and is therefore, only moving at the speed of Earth’s rotation. The rotation of Earth pulls everything inward, just like sediment or Earth’s layers. The hook is a constant force and does not pull upward on the jacket. Rather, it provides a stationary point for the “falling” jacket.

 

An example: Astronauts in the space shuttle in outer space with low or zero gravity pull a pen out of a shirt pocket and simply let it float in front of them. Unless moved by the force of the Astronaut letting it go, the pen merely stays put in the space where they let it go. The pen does not apply pressure up or down. Gravity would pull it down from its floating position, but you could not put the pen on a counter. It would float up to its mass verses any force on its surface such as an Astronaut letting it go or putting it in a certain place, which does apply pressure to the object making it move in the opposite direction when freed from the grip of the Astronaut. In outer space if two objects collide with each other, they bounce away from each other with equal force and float away in the opposite direction from the collision. On Earth and to a lesser extent the Moon, gravity plays a part in object positions relative to other objects.

 

Again, the book tries to explain this upward force on page 97 under the paragraph for co-efficient of friction and Newton’s third law states that a “normal force” exerts perpendicular force, such as a box sitting on a table where the table applies force upward against the underside of the box! The “normal force” for all objects resting on the surface of the Earth is a grounded one and therefore, are resting their mass on a stable surface. Think about a feather and its ability to lift off a surface by the slightest of wind. It has little mass and can float because of the natural air currents that even circulate inside buildings. The table is a large mass in relation to gravity and is fairly stable unless pushed by a larger mass or wind. If the table and the box were of equal force against each other the table would become wobbly as the box was sat on its surface. If the box weighs more than the table, the table will collapse under the weight of the box, and both would crash to the floor which is a larger and harder surface able to hold both the box and the table.

 

If a person sits in a chair, does the chair rise up to meet the person or is the chair sitting in its exact spot waiting for the person to sit in it? Think of it as an object (chair) sitting on an object (house) sitting on an object (ground) and all of them are being pulled down by gravity. Do you think the ground is pushing up on your feet? No? Why, then, would an object push up from the ground? It would not, else it would be light as a feather.

 

These objects are not pushing upward because the force of gravity has essentially rendered them a constant state of rest. Because, if allowed (no Earth beneath it – only gravity), the table would go down with the force of the gravity in equal parts to the table AND the box at the same time and rate. The table only stops or impedes the further downward motion of the box. There is no upward motion or tendencies of the table. Remove the house and the table would continue to plummet to Earth or the next solid mass downward.

 

I theorize there are two forces pushing down on objects within a gravitational orbit. One force is the weight of the object, and the second force is the atmospheric pressure exerted on the object, because the object weighs less at higher altitudes and is further away from the Earth’s core and the gravitational pull. This is why clouds descend and rest on the Earth from time to time because of the change in atmospheric pressure on them to stay far above the Earth. The third force is the gravitational pull on the object as the Earth rotates on its axis and around the Sun. If there were equal pressure pushing up the heavy object (such as a bowling ball), it would not fall through a vat of Jell-O when placed on the Jell-O’s surface. 

Now, if the object has the same weight as the Jell-O, we might say that it comes to “rest” on the surface with equal pressure downward. If the heavy object falls into the vat of Jell-O and the vat is made of glass, theoretically, the object could shatter the glass vat as it falls all the way to the bottom in rapid descent. True? Then, where is the equal force on the underside of the object? If the vat of Jell-O is raised in the air and the bowling ball crashes through the bottom and lands on the Earth’ sediment top layer, particles of the Earth fly out in all directions from their resting place on the Earth’s surface. The bowling ball eventually finds equal resistance on the ground and actually makes a dent where it comes to rest. Does the Earth exert upward pressure on the bowling ball or is it simply heavier or of stronger resistance than the bowling ball?

 

In the absence of gravity (as in outer space), the table would simply maintain its position unless force moved it. Thus, it can be reasonably surmised that there is no push or pull of the table against the underside of the box. If the table were to be picked up on one side, THEN we would see the force of the table working to move the box. The same can be said of the hook resting on the house waiting for the lighter jacket to rest on it. If the jacket weighed more than the hook could hold, it would break the hook and the jacket would fall to the floor. Can anyone please explain in lay terms how Newton came up with equal force up on the underside of an object as the downward force exerted on the object?

 

Just a thought…

©Copyright, Theory of Resting Force, 2010, April Graves-Minton, Love MoonEagle. All Rights Reserved.