The three equations of uniformly accelerated motion and how to choose between them

What this note covers

1. Choose a direction and describe the motion before calculating
2. Use v = u + at when displacement is not required
3. Use s = ut + one-half at² to include the initial motion
4. Use v² = u² + 2as when time is absent
5. Treat reversals and separate stages explicitly
6. Integrate motion with forces and energy only after the kinematics are clear
7. Worked two-stage motion: accelerate, then brake
8. Worked sign diagnosis: velocity reversal on an incline

8 sections · 10 key terms & formulas · 6 common mistakes