Mass

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Weight is a result of the Earth's gravity pulling the mass of the vehicle towards the center of the Earth. In terms of vehicle dynamics, the main effect of mass is to change the inertia of the vehicle which affects the way the vehicle accelerates and rotates. The weight of the vehicle also affects vehicle handling and stability.

Center of Mass/Center of Gravity

The center of mass is the point that describes the average of the mass and position of every part of the vehicle, while the center of gravity is the point that describes the average of the weight and position of every part of the vehicle. For the purposes of this article, center of mass and center of gravity will be used interchangeably.


Inertia

According to Newton's 1st Law, an object at rest stays at rest and an object in motion stays in motion. We are familiar with this concept in the form of momentum. As a general rule, engineers try to reduce the inertia of the vehicle in order to increase the maximum acceleration of the vehicle.

Polar Moment of Inertia

The Polar Moment of Inertia is defined by how far the mass is from the pivot point. When the mass is closer to either end, you have a high polar moment of inertia, and when the mass is centralized close to the pivot point, you have a low polar moment of inertia. Mid-engine cars are considered the best layout for Road Racing because of their low polar moment of inertia, since both the Engine and Driver are in between the wheel axes.

Weight Transfer

Weight transfer is a result of the vehicle accelerating. When a vehicle accelerates (for example when turning or braking), the tires create a moment that causes the vertical force applied to each tire to change. This can be seen by drawing the forces applied to a vehicle. Using Newton's 2nd Law we can calculate the forces on each tire in a steady state situation.