Chapters
Graded once a chapter has 10 timed answers: papers, part tests, chapter tests and timed past-paper sets (a 15-question strength check, Grade it, among them). Recent answers count more: one 90 days old counts half. His whole record counts as 5 questions more, so an old weakness fades but is never dropped. The line gives the score, his last 60 days and his last test.1 of 4 chapters have a note · jump to
Kinematics
Physics · Shaky 56%
No note yet.
Rotational Motion
Physics · Shaky 58% · Revised by the coach 14 Nov: Added the trap from the torque doubt; closed by the twin set
1 · Formulas and when each holds
- τ = r × F, with r from the point the torque is taken about.
- τ = Iα about a fixed axis, or about the centre of mass.
- L = Iω about a fixed axis; L is conserved when the net external torque is zero.
- Rolling without slipping: v = ωR, KE = ½mv²(1 + k²/R²).
- Parallel axis: I = I_cm + Md².
2 · Question types and the first step
- Rolling down an incline: write a = g sin θ / (1 + k²/R²) first.
- Collision with a rod: conserve angular momentum about the pivot, not linear momentum.
3 · Traps
Parallel axis: d is the distance between parallel axes, never along the axis.
Torque about a point: he took r from the axis instead of from the point asked about. Rule: mark the point first, draw r from it.
4 · My additions
- Draw the axis before writing any I.
Kinetic Theory of Gases and Thermodynamics
Physics · Shaky 63%
No note yet.
Electrostatics
Physics · Weak 40%
No note yet.