General Physics
College Intro · Science
General Physics at the introductory college level is the two-semester sequence that starts with Newtonian mechanics and moves through fluids, thermodynamics, waves, electricity and magnetism, and often a short tour of optics and modern physics. The difficulty is rarely the individual equations — it is translating a paragraph of text into a diagram, choosing a coordinate system and a system boundary, and deciding whether to attack a problem with forces, energy, or momentum. Evelyn works through problems out loud with you, asking what you know and where the setup breaks down, rather than reading solutions at you.
Start a session on General PhysicsWhat this covers
- Drawing free-body diagrams for connected, inclined, and accelerating systems, then writing Newton's second law separately along each axis
- Choosing between kinematics, work-energy, and impulse-momentum for a given problem, and recognising when mechanical energy is not conserved
- Rotational analogues: torque, moment of inertia, angular momentum conservation, and rolling without slipping constraints
- Circuit analysis with Kirchhoff's rules, series/parallel reduction, and RC charging behaviour
- Applying Gauss's law, Ampère's law, and Faraday's law with the symmetry arguments that make each one tractable
- Unit and dimensional checking, significant figures, and sanity-testing an answer's sign and magnitude before submitting
Where learners get stuck
- Treating the normal force as always equal to mg
- Every early textbook example is a block on a level floor, so the equality gets memorised as a definition instead of being derived from the perpendicular component of Newton's second law. It fails immediately on inclines, in elevators, and inside vertical loops.
- Adding 'centripetal force' to a free-body diagram as its own arrow
- The phrase sounds like a force with a source, but it is a net requirement — tension, gravity, friction, or normal force play that role. Students who add it double-count and get answers off by a factor of two.
- Believing current is consumed as it passes through a bulb or resistor
- Everyday language about 'using up electricity' maps onto current instead of energy. This produces wrong predictions about series circuits and confusion between current, potential difference, and power.
- Mixing up the sign conventions for work, heat, and potential energy
- Mechanics, thermodynamics, and electrostatics each define positive direction relative to a different reference, and courses rarely pause to reconcile them, so students carry a mechanics habit into a first-law problem.
What a session looks like
A typical session is spoken, one-on-one, and problem-driven. You bring a homework question, a past exam, or a topic you cannot follow from lecture. Evelyn asks you to describe the physical situation and the diagram you would draw, checks your axis choice and system boundary before any algebra begins, and stops you at the point where the reasoning goes wrong instead of at the final number. Where a concept is fragile — say, why friction can be the centripetal force — you will be asked to predict what happens in a modified version of the same problem.
Helpful to know first
- Comfort with algebra: solving simultaneous equations and rearranging formulas with several symbols
- Right-triangle trigonometry and resolving vectors into components
- Vector addition, subtraction, and the meaning of dot and cross products (introduced as needed)
- For calculus-based sections, basic differentiation and integration of polynomials; algebra-based sections do not require these
Questions
- Is this for algebra-based or calculus-based physics?
- Both. Evelyn asks which sequence you are in at the start and keeps derivatives and integrals out of the explanation for algebra-based courses, or uses them for calculus-based ones where they make the reasoning shorter.
- I understand the lectures but freeze on the homework problems. Can that be fixed?
- That gap is usually about problem setup, not concepts. Sessions focus on the first two minutes of a problem — identifying the system, the forces, the known and unknown quantities, and which conservation law applies — which is the part lectures tend to skip.
- Can Evelyn help with physics lab reports?
- Evelyn can discuss error propagation, graph linearisation, and what a slope physically represents, and can talk through why your data deviates from theory. It does not write reports for you.
- Which topics in intro physics do students usually find hardest?
- Rotational dynamics, static equilibrium with extended bodies, and the magnetism half of the second semester are the most common trouble spots, largely because they require careful geometry before any equation is useful.