1
Identify the forces on a block M1 AP engaged adds A free-body diagram lists only real forces from real agents.›
2
Choose axes on an incline M2 AP adds Axes parallel and perpendicular to the surface isolate the constrained direction.›
3
Find the normal force on an incline M3 AP flagship adds The normal force balances only the perpendicular component of weight.›
4
Static friction threshold M4 AP flagship adds Static friction adjusts up to a maximum; it is not automatically μs N.›
5
Pulley constraint M5 AP C adds A single inextensible string fixes equal-magnitude accelerations.›
6
Two-block system: choosing the system M6 AP C flagship adds Internal/external depends entirely on the system boundary.›
7
Circular motion: force direction M7 F=ma flagship adds Uniform circular motion has inward acceleration even at constant speed.›
8
Wedge/block constraint M8 F=ma adds A moving support changes the ground-frame acceleration constraint.›
9
Non-inertial frame, intro M9 USAPhO adds In an accelerating frame, add a pseudo-force -m a_frame.›
10
Rolling-energy bridge M10 USAPhO flagship adds A rolling constraint turns rotational energy into a v-only expression.›
11
Apparent weight in an elevator M11 AP adds A scale reads normal force, not gravitational weight.›
12
Signed string constraints M12 AP C adds A length constraint must respect your coordinate signs.›
13
Friction from relative motion M13 F=ma adds Kinetic friction opposes slipping at the contact, not the object's absolute velocity.›
14
Banked curve speed regimes M14 F=ma flagship adds Static friction direction on a banked curve depends on impending slipping.›
15
Projectile components M15 AP adds Horizontal velocity and vertical acceleration are independent when only gravity acts.›
16
Block on an accelerating wedge M16 F=ma flagship adds When the surface itself accelerates, resolve on fixed axes — the incline shortcut N = mg cos θ no longer applies.›
17
Stacked blocks: the friction budget M17 F=ma adds Static friction on the upper block caps the acceleration the pair can share.›
18
The block on a block M18 F=ma flagship adds When two bodies move together, friction is the only thing accelerating the upper one — and it has a ceiling.›
19
Two blocks, one incline M19 AP adds One string means one acceleration magnitude; pick a positive direction along the motion and keep it.›