9th Grade Physics Study Guide
Motion and Forces
● Speed and Velocity:
○ Speed measures how fast something moves (distance/time).
○ Velocity includes speed and direction (e.g., 50 mph north).
● Acceleration:
○ Acceleration is the rate of change of velocity (change in velocity/time).
○ Positive acceleration means speeding up, negative means slowing down.
● Newton's Laws of Motion:
○ 1st Law (Inertia): Objects at rest stay at rest, objects in motion stay in motion
unless acted upon by an unbalanced force.
○ 2nd Law (Force and Acceleration): Force equals mass times acceleration (F =
ma).
○ 3rd Law (Action-Reaction): For every action, there is an equal and opposite
reaction.
● Friction:
○ Friction is a force that opposes motion between two surfaces.
○ Types of friction include static (objects at rest), sliding (objects sliding), and rolling
(objects rolling).
Energy and Work
● Types of Energy:
○ Kinetic Energy: Energy of motion.
○ Potential Energy: Stored energy (e.g., gravitational, elastic).
○ Thermal Energy: Energy related to heat.
○ Electromagnetic Energy: Energy of light and other electromagnetic waves.
○ Chemical Energy: Energy stored in chemical bonds.
○ Nuclear Energy: Energy stored in the nucleus of an atom.
● Work:
○ Work is done when a force moves an object a distance.
○ Work = force x distance (W = Fd).
● Conservation of Energy:
○ Energy cannot be created or destroyed, only transformed from one form to
another.
Waves
● Types of Waves:
○ Mechanical Waves: Waves that require a medium to travel (e.g., sound waves,
water waves).
Motion and Forces
● Speed and Velocity:
○ Speed measures how fast something moves (distance/time).
○ Velocity includes speed and direction (e.g., 50 mph north).
● Acceleration:
○ Acceleration is the rate of change of velocity (change in velocity/time).
○ Positive acceleration means speeding up, negative means slowing down.
● Newton's Laws of Motion:
○ 1st Law (Inertia): Objects at rest stay at rest, objects in motion stay in motion
unless acted upon by an unbalanced force.
○ 2nd Law (Force and Acceleration): Force equals mass times acceleration (F =
ma).
○ 3rd Law (Action-Reaction): For every action, there is an equal and opposite
reaction.
● Friction:
○ Friction is a force that opposes motion between two surfaces.
○ Types of friction include static (objects at rest), sliding (objects sliding), and rolling
(objects rolling).
Energy and Work
● Types of Energy:
○ Kinetic Energy: Energy of motion.
○ Potential Energy: Stored energy (e.g., gravitational, elastic).
○ Thermal Energy: Energy related to heat.
○ Electromagnetic Energy: Energy of light and other electromagnetic waves.
○ Chemical Energy: Energy stored in chemical bonds.
○ Nuclear Energy: Energy stored in the nucleus of an atom.
● Work:
○ Work is done when a force moves an object a distance.
○ Work = force x distance (W = Fd).
● Conservation of Energy:
○ Energy cannot be created or destroyed, only transformed from one form to
another.
Waves
● Types of Waves:
○ Mechanical Waves: Waves that require a medium to travel (e.g., sound waves,
water waves).
