2.6.A—Describe the gravitational interaction between two objects or systems with mass

Describe the gravitational interaction between two objects or systems with mass.

• Newton’s law of universal gravitation describes the gravitational force between two objects or systems as directly proportional to each of their masses and inversely proportional to the square of the distance between the systems’ centers of mass. Relevant equation: FG r g 12 2= mm
  • i. The gravitational force is attractive.
  • ii. The gravitational force is always exerted along the line connecting the center of mass of the two interacting systems.
  • iii. The gravitational force on a system can be considered to be exerted on the system’s center of mass.
• A field models the effects of a noncontact force exerted on an object at various positions in space. TOPIC 2.6 Gravitational Force
  • i. The magnitude of the gravitational field created by a system of mass M at a point in space is equal to the ratio of the gravitational force exerted by the system on a test object of mass m to the mass of the test object. Derived equation: g F m G M r g 2== 
  • ii. If the gravitational force is the only force exerted on an object, the observed acceleration of the object (in m/s2) is numerically equal to the magnitude of the gravitational field strength (in N/kg) at that location.
• The gravitational force exerted by an astronomical body on a relatively small nearby object is called weight. Derived equation: Fm gWeightg==