Physics is the brain of engineering; the center of gravity and pivot points are the heart. In our day-to-day life without these two properties, nothing would exist. Because the center of gravity predicts the behavior of a moving body when acted on by gravity. Here is an example to explain it better.
Have you seen the Thanjavur doll? This doll has three parts the bottom stand, a cone-like structure, and the head portion. The cone-shaped gown and the head are built over the stand. The doll starts to oscillate left and right. This happens because the total weight is concentrated at its bottom-most point. This is known as the center of gravity. The pivot point is also related to the center of gravity.
The point that an object rotates around. The play top is a suitable example to explain. A rope is tied over the top and thrown towards the ground, and the top starts to rotate. The nail continues to spin at the same point. This point is known as the pivot point.
The center of gravity is calculated by taking the sum of its moment divided by the overall weight of the object. The moment is the product of the mass and its location as measured from the origin.
Centre of gravity in aircraft :
These two concepts have high-impact applications in aerospace and aerodynamics. When a plane takes off, if the center of gravity is too forward, the flow of air over the elevators will not generate enough force to lift the nose part of the plane and allow the wings to generate lift. The pilot will not be able to get into the air and must abort the plane’s take-off.
If the center of gravity is too far, the plane will nose upwards during the takeoff and climb. The pilot will not be able to generate enough force through elevators to lower the nose, and as speed increases the nose will continue to elevate steeply. When the plane stalls, it crashes. Hence pilots and engineers designing the aircraft must verify if the center of gravity stays within the bound.
It is also applied in manufacturing vehicles; when the center of gravity of vehicles is focused towards the bottom, the roll-over accidents are widely reduced. The battery pack makes the center of gravity focused on the bottom of the car compared to diesel engines which focus the center of gravity on the middle of the car. Hence electric vehicles have a high safety rate when compared to fuel vehicles.
Applications continue in biomechanics. It is considered for stability analysis for joints in humans.
Thus, the center of gravity and pivot point are two droplets from the oceans of engineering physics. In the next blog, you will get to read more fascinating topics.