Physics, grade 9
23 topics for grade 9, 204 exercises. Each one starts with an explanation, then practice that adapts: get it right and the difficulty rises, get it wrong and the tutor takes the step apart.
Topics in this grade
Momentum and Impulse
Momentum measures how much motion a moving object carries.
6 exercises
Kinematics
Kinematics describes how a moving object's position and speed change over time.
9 exercises
Dynamics
Dynamics studies why a moving object speeds up, slows down, or changes direction.
9 exercises
Conservation Laws
Conservation laws say some totals in a closed system never change.
9 exercises
Circular Motion
An object in uniform circular motion moves at constant speed along a circular path.
9 exercises
Gravity and Universal Gravitation
Gravity is the pull every object with mass exerts on every other object with mass.
9 exercises
Magnetic Field Basics
A magnetic field is a region where magnetic forces act, around a magnet or wire.
9 exercises
Electromagnetic Induction
Electromagnetic induction creates an electric current by changing the magnetic field through a loop of wire.
9 exercises
Alternating Current
Alternating current periodically reverses direction, unlike direct current which flows one way.
9 exercises
Electromagnetic Waves
An electromagnetic wave combines oscillating electric and magnetic fields, traveling even through a vacuum.
9 exercises
Harmonic Oscillations
A harmonic oscillation is a repeating back-and-forth motion, like a pendulum or a spring.
9 exercises
Mechanical Waves
A mechanical wave carries energy through a medium without carrying the medium itself along.
9 exercises
Sound and Acoustics
Sound is a longitudinal mechanical wave that travels through air, water, or solids.
9 exercises
Geometric Optics
Geometric optics treats light as straight rays that reflect and refract at surfaces.
9 exercises
Wave Optics
Light behaves as a wave and can interfere and diffract, not just travel in straight rays.
9 exercises
Bohr Atomic Model
The Bohr model pictures an atom as a tiny nucleus with electrons orbiting at fixed distances.
9 exercises
Radioactivity
Radioactivity is the spontaneous decay of an unstable nucleus, releasing particles or energy.
9 exercises
Nuclear Reactions
A nuclear reaction changes the nucleus of an atom.
9 exercises
Nuclear Fission
Nuclear fission splits a heavy nucleus into two lighter nuclei, releasing energy and extra neutrons.
9 exercises
Nuclear Fusion
Nuclear fusion joins two light nuclei into one heavier nucleus, releasing energy.
9 exercises
Solar System
The Solar System is the Sun plus the planets, moons, asteroids, and comets orbiting it.
9 exercises
Stellar Evolution
Stellar evolution describes how a star changes over its lifetime.
9 exercises
Galaxies and Cosmology
Galaxies are huge systems of billions of stars, gas, and dust, held together by gravity.
9 exercises
Where this leads
These topics feed DTM Physics, NMT Physics, ZNO Physics.
Start with a 15-minute diagnostic
It finds which of these topics are solid and which are shaky, then builds the plan from there.
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