Physics
A self-study course in mechanics for high school physics. Work through the lessons in order: each one explains the ideas, lets you test them in simulations, and checks your understanding as you go.
0 of 18 completed
Forces and Newton's laws
What forces are, how to draw them, and the three laws that connect force to motion.
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1
35 minCompleted
What a force is, and how to draw one
Forces as pushes and pulls, the newton, contact and field forces, and free-body diagrams.
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2
40 minCompleted
Inertia, net force and equilibrium
Why moving things keep moving, how to add forces into one net force, and what equilibrium means.
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3
30 minCompleted
Newton's second law
How net force and mass decide acceleration, and how to use the second law in problems.
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4
25 minCompleted
Newton's third law
Forces come in pairs. Find the pairs, and see why they never cancel each other.
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5
40 minCompleted
Weight, the normal force and friction
Mass versus weight, the normal force on flat ground and on ramps, and static and kinetic friction.
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6
40 minCompleted
Friction problems, air resistance and the fundamental forces
Solve problems with angled pulls and ramps, see how terminal speed arises, and meet the four fundamental forces.
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7
Lab45 minCompleted
Forces and friction lab
An open lab: build free-body diagrams, test Newton's laws, and explore friction and ramps by dragging forces.
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8
Unit review45 minCompleted
Review: forces and Newton's laws
A summary of the unit and a mixed set of practice questions with full solutions.
Work and energy
Work, the main forms of mechanical energy, conservation of energy and power.
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9
35 minCompleted
Work
What physicists mean by work, why only part of a force counts, and when work is positive, negative or zero.
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10
35 minCompleted
Kinetic energy and the work-energy theorem
The energy of motion, why speed matters so much, and how net work changes kinetic energy.
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11
35 minCompleted
Potential energy
Stored energy: gravitational potential energy, choosing a zero level, and elastic energy in springs.
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12
40 minCompleted
Conservation of mechanical energy
How kinetic and potential energy trade places, how to solve problems with energy, and what friction changes.
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13
30 minCompleted
Power
How fast energy is transferred, two ways to calculate power, and a first look at mass as energy.
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14
Unit review45 minCompleted
Review: work and energy
A summary of the unit and a mixed set of practice questions with full solutions.
Momentum and collisions
Momentum, impulse, conservation of momentum, and what happens to energy in collisions.
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15
45 minCompleted
Momentum and impulse
Momentum as mass times velocity, and how force and time together change it.
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16
40 minCompleted
Conservation of momentum
Why the total momentum of interacting objects stays the same, from billiard balls to rockets.
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17
45 minCompleted
Elastic and inelastic collisions
Objects that stick, objects that bounce, and what happens to kinetic energy in each case.
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18
Unit review50 minCompleted
Review: momentum and collisions
A summary of the unit, simulations of harder problems, and practice questions with full solutions.
New lessons and books by email
One short email when a new lesson or book is released. No other mail.
Opens your email app with a short message to [email protected].