Grade 12 · Theory
Free fall revisited
Vertical projectile motion · about 3 min
A projectile with gravity acting downward throughout.A vertical projectile is any object moving under gravity alone, up or down.
Key points- Acceleration is always 9,8 m·s⁻² downward, at every point including the top.
- Choose a positive direction and apply it to every vector.
- At maximum height, velocity is zero — this is the key substitution.
- Time up equals time down when the start and end heights match.
- Projectile — an object moving under gravity only.
EXAM TIP
writing "up is positive, so g = −9,8 m·s⁻²" at the top of your answer prevents nearly every sign error that follows.