Universal Gravitational Law
The gravitational attraction between two objects depends upon the mass of the objects and the distance between them. This relationship is often called the "Universal Law of Gravitation" and can be expressed as
F = kG m1 m2 / r2 (1)
where
F = gravitational force (N)
kG = 6.668×10-11 (Nm2/kg2) = the Universal Gravitation Constant
m = mass of object (kg)
r = distance between objects (m)
Example - The Gravitational Force (Weight) Acting on a Person on Earth's Surface
The gravitational force (or weight) acting on a person with mass 70 kg on the earth's surface (6.37×106 m from the earth's center) can be calculated as
F = (6.668×10-11 Nm2/kg2) (5.98×1024 kg) (70 kg) / (6.37×106 m)2
= 688.1 (N)
- 5.98×1024 (kg) = mass of earth
Related Topics
• Dynamics
Motion of bodies and the action of forces in producing or changing their motion - velocity and acceleration, forces and torque.
• Mechanics
The relationships between forces, acceleration, displacement, vectors, motion, momentum, energy of objects and more.
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