First Equation of Motion
Final velocity under constant acceleration.
v = u + at
1What it means
For motion with constant acceleration, the final velocity equals the starting velocity plus the velocity gained over time.
2Variables
| Symbol | Meaning |
|---|---|
| v | Final velocity (m/s) |
| u | Initial velocity (m/s) |
| a | Acceleration (m/s²) |
| t | Time (s) |
3Worked examples
Example 1 Worked solution
Q. A car starts at 10 m/s and accelerates at 2 m/s² for 5 s. Find its final speed.
- v = u + at = 10 + 2 × 5.
- = 10 + 10.
✓ v = 20 m/s
4Where it's used
- ✦Free-fall problems (a = g ≈ 9.8 m/s²).
- ✦Acceleration and braking calculations.
5Tips & common mistakes
- !Take a as negative when the object slows down (deceleration).