Physics – What Does Gravity Do?
If there is something that everyone understands, it’s that work and energy are the same thing. We cannot exist without work, because without it we cannot live. What many don’t understand, however, is how this works in practice. To simplify things, let’s think about what happens when two boxes, A and B, are balanced on top of each other.
In Physics, work is simply the energy changed into or from an object through the application of pressure or force. In its most simple form, it can be described as the resultant product of physical displacement and force. Put simply, the more work that is applied, the greater the kinetic energy of the object will be. Put another way, the greater the work that is done, the stronger the object will be. Put those two together, and you’ll find that the bigger the displacement, the higher the work energy the object has.
Put another way, let’s imagine that we have this box that A sits on top of. Now we apply a downward force, parallel to the surface of the box, to it. What will happen? The object with it will begin to move in a new direction, in the direction of where A’s position is. Because A and B are in constant motion with respect to one another, they will always be moving toward (or away from) the centre of the surface.
So let’s assume now that we have a waiter standing on top of a table. What will happen if we apply a constant force, parallel to the waiter’s motion, to the table, and the waiter keeps walking forward in the same direction? This, in turn, will continue until the waiter stops, at which point the waiter reverses his motion, and starts walking backward.
We can see from this example that the magnitude of the displacement required by an object, against an external force, is dependent upon the angle of affixation. Now let us suppose that we take the example even further, and assume that the angle of affixation, which is, say, 90 degrees, and that the object’s velocity is, say, two metres per second, then we would say that the force required to move the object, in the direction of where it wants to go, is two times its velocity. This means that the force, when acting on the object, needs to be acted upon an angle, which is not the same as the normal one. This results in the displacement being twice as large. It is for reasons like this that most people prefer to work with their hands rather than their legs, because the motions of the hands are not parallel to the horizontal axis, whereas the movements of legs are.
For all these reasons, I think it safe to conclude that gravity plays a very important role in the dynamics of the human body. Let me now turn to the other side of the equation. Gravity does not play a crucial role in the motion of objects at rest, but it does play a vital role when the objects are being moved around, or are being put into motion. To put it simply, when you lift something, you use some of your weight in lifting the object, and the rest of your weight moves with the object in the direction determined by the momentum of motion. The torque, which you feel as your feet slipping along with the weight, is actually just the sum of the force that your upper body is trying to carry around with it, due to gravity.