25 topics
Physics help, starting with the free-body diagram
The single highest-value habit in physics is drawing the free-body diagram before touching an equation, and it is the step nearly everyone skips. Most wrong answers in mechanics are not algebra errors — they are a missing force, or a force drawn in the wrong direction, and no amount of correct algebra recovers from that.
Where students get stuck
Which kinematics equation do I use?
List what you have and what you want. There are five variables — initial velocity, final velocity, acceleration, displacement, time — and each equation is missing exactly one of them. Pick the equation missing the variable you neither have nor want. That reduces a memorised set to a lookup, and it works every time as long as acceleration is constant.
Normal force is not always mg
It equals mg only on level ground with no vertical acceleration and nothing pushing down or lifting up. On an incline it is mg cos θ. In an elevator it changes with the acceleration. If someone leans on the block, it goes up. Treating N as mg by reflex is one of the most reliable ways to lose marks on an incline or elevator question.
Energy or momentum — which one is conserved?
Momentum is conserved in every collision with no external force, full stop. Kinetic energy is only conserved if the collision is elastic, and 'the objects stick together' is the standard signal that it is not. If a problem says 'perfectly inelastic', use momentum for the collision and only then account for the energy that went into deformation and heat.
Series and parallel circuits
Series shares current, parallel shares voltage. That one sentence resolves most circuit questions, because it tells you which quantity is the same across components and therefore what to solve for first. Total resistance goes up in series and down in parallel — a parallel combination is always smaller than the smallest branch, which is a useful sanity check on your arithmetic.
What's covered
Physics topics you can work through with a tutor, generate practice on, or turn into flashcards and a study plan.
Mechanics
- Vectors and components
- Kinematics in one and two dimensions
- Projectile motion
- Newton's laws and free-body diagrams
- Friction, tension, and inclines
- Circular motion and centripetal force
- Gravitation and orbits
Energy and momentum
- Work, kinetic and potential energy
- Conservation of energy and power
- Impulse and momentum
- Elastic and inelastic collisions
- Centre of mass
- Torque, rotational motion, and angular momentum
Waves and thermodynamics
- Simple harmonic motion, springs, and pendulums
- Wave properties, interference, and standing waves
- Sound, resonance, and the Doppler effect
- Reflection, refraction, lenses, and mirrors
- Heat, temperature, and the laws of thermodynamics
Electricity, magnetism, and modern physics
- Coulomb's law and electric fields
- Electric potential and capacitance
- Current, resistance, and Ohm's law
- Series and parallel circuits, Kirchhoff's rules
- Magnetic fields and forces on moving charges
- Electromagnetic induction and Faraday's law
- The photoelectric effect, atomic models, and nuclear decay
Physics questions
Will it draw the free-body diagram?
Yes, on the whiteboard, before the algebra — which is the point. Seeing which forces were drawn and which were left out is usually enough to find your own error without being told the answer.
Does it cover AP Physics 1, 2, and C?
The topics above span all three. AP Physics C is calculus-based, so if you are in it, say so and the explanations will use derivatives and integrals rather than the algebra-only versions.
I understand the concept but I can't do the problems.
Extremely common in physics, and it is a setup problem rather than a concept problem. Working through problems out loud — where the tutor stops you at the setup rather than the arithmetic — targets exactly that gap.
Stuck on physics right now?
Talk it through out loud, share your screen, and watch it worked out step by step on a whiteboard.
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