Chapter 2 Study Guide

Laws of Motion

Rules or principles that describe and predict the behavior of objects in the universe based on mass and force.

Gravity

The attractive force between any two bodies in the universe.

Weight

The measure of the force of gravity on an object, which remains the same regardless of location.

Mass

The amount of matter present in an object, which also remains the same regardless of location.

Predictability

The central principle of science, where observations over time allow for predictions about the positions of stars and planets.

Stonehenge

A large circular monument used as an astronomical calendar to mark the passage of seasons.

Spherical Models

Ancient belief that the universe was perfect and all movements of stars and planets were based on spherical models.

Elliptical Orbits

Subsequent study revealed that planetary orbits are actually elliptical, rather than spherical.

Mechanics

The branch of science that deals with the motions of objects.

Newton's Laws of Motion

Three universal laws that act in the universe, describing inertia, acceleration, and equal and opposite reactions.

Inertia

The tendency for an object to remain at rest or in uniform motion.

Uncertainty

The inability to accurately predict events with absolute certainty, despite the laws of motion.