Gravitational Force Near Earth

Air resistance (2)

• Frictional force caused by the air

• Acts in the opposite direction of the object’s motion

What are the 2 factors that impact air resistance? (2)

Cross-sectional area

• Larger cross-sectional areas experience more air resistance than smaller areas

Object’s Speed

• Aster moving objects experience more air resistance

Terminal speed

The maximum constant speed reached by a falling object.

Gravitational force field

• A region of space surrounding an object that can exert a force on other objects

• The field exerts a force only on objects placed within that region that can interact with that force

• Represented by a series of lines directed radially inward toward the mass

Gravitational field strength

• Determines the magnitude of a bodi’s gravitational force field at a particular location near its surface

• Vector quantity

• Always points toward the Earth’s center

• Has the same magnitude as the acceleration due to gravity at that location (same symbol)

• measured in N/kg

Universal law of gravitation

• There is a gravitational force on any object

• If the objects have the masses m₁ and m₂ and their centers are separated by a distance r, the magnitude of the gravitational force on either object is proportional to the product of m₁ and m₂ and inversely proportional to r²