Have you ever wondered why an object bounces a few times and then stops when you throw it? Have you ever wondered why when you nudge a pencil, it rolls on the table and then stops? Why is it that an object moves, only to inevitably stop?
Inertia is the tendency of an object to resist any change in it’s motion. This concept is important in the fields of engineering, and physics.
On Earth, two things tend to decrease the speed of moving objects. Friction causes the object to slow down and come to a position of rest, also known as inertia of rest. So when you roll that pencil, there is actually friction going against the movement of the pencil, or any other factor around it. Since there is also gravity on Earth, the gravity just generates friction. Both of these factors cause an object to slow down and come to ’ inertia of rest’.
An object will stay at rest or stay in motion unless acted on by a net external force, whether it results from gravity, friction, contact, or some other source.
So, is there still friction when an object isn’t moving?
Friction is the primary force that will keep the two objects stationary with respect to each other. Without friction, the slightest force applied will cause the object to move. So, in a manner, you can view friction as what can stop an object from moving; an object still experiences friction even when it isn’t moving.
How can this be utilized?
Well, if you can get an object to have little to no friction, then the object could, technically, move indefinitely.
Examples of objects that work against friction are air-barriers, and superconductors; both of these examples use entirely different concepts to work against friction.
Air barriers are often used in hovercrafts. The skirt of a hovercraft allows the air to flow out of the bottom of the hovercraft evenly, allowing the hovercraft to glide or float against the surface when it is moved.
Superconductors’ resistance drops abruptly to zero when the material used is cooled below its critical temperature. Superconductivity is a quantum mechanical phenomenon where the magnetic field is locked in 3-dimensions. The magnetic field inside of it stays the same, so the object can be spun around, be put at different angles, different heights, or even upside down, and it still remains suspended in space.
The potential velocity of an object could be increased just by not allowing friction to work against it.
Consider my post on quantum levitation for more information ( LINK ).