Gravity and Motion Vocabulary

A collection of key terms and concepts regarding gravity, falling objects, orbiting, and projectile motion based on the provided lecture notes.

Aristotle

An ancient Greek philosopher who thought that the rate at which an object falls depended on the object's mass.

Galileo Galilei

An Italian scientist who argued that the mass of an object does not affect the time the object takes to fall to the ground.

Acceleration Due to Gravity

The rate at which all objects accelerate toward Earth, which is $9.8\,m/s^2$.

$$\Delta v = g \times t$$

The equation used to calculate the change in velocity of a falling object, where $g$ is $9.8\,m/s^2$ and $t$ is time in seconds.

Air resistance

The force that opposes the motion of objects through air; its magnitude depends on the size, shape, and speed of the object.

Terminal velocity

The constant velocity of a falling object when the force of air resistance is equal in magnitude and opposite in direction to the force of gravity.

Free fall

The motion of a body when only the force of gravity is acting on the body, which can only occur where there is no air.

Vacuum

A place in which there is no matter.

Orbiting

The path followed when an object is traveling around another object in space, combining forward motion and free fall.

Centripetal force

The unbalanced force that causes objects to move in a circular path; the term means "toward the center."

Projectile motion

The curved path that an object follows when thrown, launched, or otherwise projected near the surface of Earth.

Horizontal motion

Motion that is parallel to the ground; in projectile motion, its velocity is constant after the object is released.

Vertical motion

Motion that is perpendicular to the ground; in projectile motion, gravity pulls the object down at an acceleration of $9.8\,m/s^2$.