High school · Science
Physics
Physics uses models, measurements, and mathematics to explain motion, forces, energy, waves, and electricity.
What you will learn
- Describe motion with graphs and equations.
- Analyze forces using Newton's laws.
- Track energy and momentum.
- Explore wave behavior.
- Explain basic electric circuits.
Common challenges
Choosing a model
Before selecting a formula, sketch the situation and list what is known. State assumptions such as negligible air resistance.
Direction and signs
Velocity and force include direction. Choose a positive direction and use it consistently.
Graphs versus paths
A position-time graph is not a drawing of the route. Read what the axes measure, then interpret slope or area as appropriate.
Key concepts
- Motion
- Position describes location relative to a reference point. Velocity describes how position changes, and acceleration describes how velocity changes.
- Net force
- The vector sum of forces determines acceleration through F_net = ma for constant mass.
- Energy conservation
- Energy transfers between objects and changes form. A complete accounting includes energy transferred to surroundings, such as by heating.
- Momentum
- Momentum is mass times velocity. Total momentum stays constant for a system when the net external force is zero.
- Waves
- Waves transfer energy through disturbances. Frequency, wavelength, and wave speed are related by v = f times wavelength.
- Electric circuits
- A closed conducting path can carry current. Potential difference transfers energy per unit charge, and resistance affects current.
How to prepare
- Practice rearranging equations such as v = d/t.
- Review slope and area on simple graphs.
- Convert between common metric units.
- Review right triangles and basic sine and cosine.
Study habits that help
- Draw a force diagram before writing force equations.
- Estimate an answer's size before calculating.
- Check units as carefully as numbers.
- Explain whether your result makes physical sense.
What to expect
- Typical workload
- Moderate
- Time outside class
- Typically about 4 to 6 hours outside class; the math level and school workload vary.
- Pace
- New models usually come with worked problems, experiments, and applications.
- How it is usually graded
- Problem sets, tests, quizzes, labs, and lab reports commonly determine grades.
Skills that help
- Algebra
- Diagram drawing
- Graph interpretation
- Unit checking
What teachers usually expect
- State assumptions and show reasoning.
- Include directions and units.
- Follow laboratory and electrical safety instructions.
Before you start
- Typical Algebra 1 skills, with Algebra 2 helpful for many versions
- Basic graphing
- Geometry and trigonometry as needed for the course's math level
These are general descriptions of a typical course. Workload, pace and prerequisites differ by school and instructor, so check with your counselor, advisor or the course catalog.
Where it can lead
- Physics
- Engineering
- Astronomy
- Computer science
- Architecture
Flashcards
Card 1 of 10
Practice questions
Question 1 of 6
An object travels 20 m in 4 s. What is its average speed?
Vocabulary
- Scalar
- A quantity with magnitude but no direction.
- Vector
- A quantity with both magnitude and direction.
- Displacement
- The change in position from start to finish.
- Inertia
- An object's resistance to changes in velocity.
- Work
- Energy transferred by a force acting through a displacement.
- Power
- The rate of energy transfer or work.
- Wavelength
- The distance between corresponding points on successive wave cycles.
- Resistance
- The ratio of potential difference to current for a circuit element at a given operating point.