地球上の重力による加速度

Acceleration due to gravity is the rate at which objects accelerate toward Earth's surface when falling freely under gravitational force alone. On Earth, this value is approximately 9.8 meters per second squared (m/s²). This constant applies to all objects regardless of mass, making it a fundamental constant in physics and mechanics.

Gravitational acceleration is constant near Earth's surface because the gravitational force acting on an object is proportional to its mass, and this force divided by mass yields a constant value. The distance from Earth's center remains relatively unchanged at the surface, so the acceleration remains approximately 9.8 m/s² for all objects in free fall.

Mass does not affect an object's acceleration due to gravity. Although gravitational force increases with mass, the acceleration remains constant at 9.8 m/s² because force and mass are proportionally related. This means a feather and a bowling ball accelerate at the same rate when falling freely in a vacuum.

Weight is the gravitational force exerted on an object and is calculated by multiplying mass by gravitational acceleration (W = mg). Since gravitational acceleration on Earth is 9.8 m/s², an object's weight increases proportionally with its mass. Weight varies with location, while mass remains constant.

Gravitational acceleration decreases slightly with increasing altitude because distance from Earth's center increases. At higher elevations, objects experience slightly less gravitational acceleration than the standard 9.8 m/s² at sea level. This effect becomes more pronounced at extreme altitudes, such as in space or on mountains.

Gravitational acceleration is essential for calculating forces, motion, and energy in mechanical systems. Engineers use the 9.8 m/s² value to determine structural loads, design safety systems, and predict object motion. Accurate gravitational acceleration values ensure reliable predictions of system behavior and component performance.