Eli5: when you “lower the center of gravity” on something ( car, or whatever) does it actually have anything to do with gravity?
In: Physics
It would probably be more accurate to call it the center of mass. You are lowering the point of center of mass. Gravity does not really change at all.
Gravity acts on mass. If you were to tie a string to the car and have it pulled down by gravity, that’s where the string would be attached.
It does have something to do with gravity. When gravity is uniform is is equal to the center of mass of an object, on earth gravity is close enough to uniform for almost everything
For a lot of stability and other considerations, you can imagine an object’s mass is in that location.
Look at this image [https://media.ed.science.psu.edu/h5p/embed/4474?entity_iframe=1](https://media.ed.science.psu.edu/h5p/embed/4474?entity_iframe=1) the dot is the center of mass of the object. It will fall over if the center of mass is outside the contact point on the surface. 1, 2 and 3 have the center of mass in the contact point and will not fall over but 3 have it outside and will fall over.
3 would be a car with a high center of gravity and 4 with a low center of gravity. How well a car handles a tight is similar to the box above on the inclined plane. The car will tip over easier if the center of mass it higher.
Put a pen on your fingertip, and it will rotate one way or the other and fall off. There’s more of the pen’s mass on one side than there is on the other, so gravity pulling that side downwards more makes the rotation (and fall) happen.
Now practice placing the pen on your fingertip in different spots until it balance. You’ve now made the rotation from gravity exactly equal on both sides, so they cancel out, so it just sits there. You have found the *center of gravity* – it’s not the spot where the pen’s *length* is centered on your finger, but instead it’s the spot where the *gravitational forces* are *centered*.
Just think of the phrase, Top Heavy.
If a semi truck has a very tall load that makes it very, “wobbly,” when the truck makes a sharp turn it might topple over. The load makes the truck unstable when changing direction.
If that same load was repositioned on the trailer some to the front and some to the rear, the truck would not be so wobbly and would be able to change direction in a turn without toppling over.
When more of the weight of a vehicle is positioned low and in the center, the force of gravity is less likely to pull the vehicle against the direction that the driver wants the vehicle to go.
Think of a waiter carrying a service tray with 20 plates. If the waiter stacks all 20 plates on top of each other in a tall tower, when the waiter changes their direction to go around a corner the momentum of the stack will resist the change and “topple.”
If the waiter spreads out the 20 plates across the whole surface of the tray only going up 3 or 4 high, they will be able to change direction without toppling the load.
The center of gravity in a uniform gravitational field is also the center of mass.
When gravity acts on a rigid body (doesn’t flex), you can assume that all the gravity acts on that single point, rather than acting on every individual point of mass on the object.
youre lowering the center of the weight basically, for example if all of your weight would go to your feet it would make you heavier
Imagine you are floating in space, far from any objects large enough to exert significant gravity on you. A car floats up to you, and you push it. The car will spin around its center of mass.
Now, you magnet some weights to the bottom of the car, changing the center of mass, and you push the car again: now the car spins around the new center of mass.
Changing the center of mass doesn’t rely on gravity to have an effect. The behavior of any force pushing the car will be dictated by the center of mass.
Center of gravity and center of mass are the same if you assume that gravity acts the same on all parts of the car. (This is approximately right, but with very large objects like planets, the center of mass and center of gravity are different because gravity will effect different parts of the planet differently depending on their distance from whatever is generating the gravity.)
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