How does the gravitational field strength vary with height above the Earth's surface?

The gravitational field strength decreases with increasing height above the Earth's surface.

As an object moves away from the Earth's surface, the distance between the object and the Earth's center increases. This results in a decrease in the gravitational force acting on the object, which is proportional to the inverse square of the distance between the object and the Earth's center. As a result, the gravitational field strength decreases with increasing height above the Earth's surface. To understand more about how gravitational forces operate, you might find the Magnetic Field Basics page helpful, despite its primary focus on magnetic fields, as it covers fundamental concepts applicable to fields in general.

The gravitational field strength at a height h above the Earth's surface can be calculated using the formula g = GM/(R+h)^2, where G is the gravitational constant, M is the mass of the Earth, and R is the radius of the Earth. As the height h increases, the denominator (R+h)^2 increases, resulting in a decrease in the gravitational field strength. For a more detailed explanation of this equation, visit the Gravitational Field Strength page.

At the Earth's surface, the gravitational field strength is approximately 9.81 N/kg. As an object moves away from the Earth's surface, the gravitational field strength decreases. For example, at a height of 100 km above the Earth's surface, the gravitational field strength is approximately 8.7 N/kg. At a height of 1000 km, the gravitational field strength is approximately 6.6 N/kg.

In summary, the gravitational field strength decreases with increasing height above the Earth's surface due to the inverse square law of gravitational attraction. This has important implications for satellite orbits and space travel. Additionally, the concept of the Universal Law of Gravitation underpins these observations, explaining the gravitational interactions at various distances from the Earth. For further reading on the implications of gravitational variations at different altitudes, the Defining Gravitational Potential page can provide deeper insights.