Physics 11 · Physics · Lesson 2.4
Free Fall & Projectiles
- Level
- Grade 11
- Reading time
- 11 min reading
- Review
- Last reviewed 2026-09-03
- Standard
- Accuracy standard
- Errata
Abstract
Motion under gravity.
What is projectile motion?
Short answer
Projectile motion is the curved path of an object thrown or launched near Earth’s surface, moving under gravity alone. Its horizontal and vertical motions are independent: the horizontal velocity stays constant while the vertical motion accelerates downward at about 9.8 m/s². Combining the two gives a parabolic trajectory. Air resistance is usually neglected in introductory analysis.
Concept preview
What you will be able to do
- 01Apply the kinematics equations to free fall with a = g
- 02Treat horizontal and vertical motion of a projectile independently
- 03Solve for time of flight, range and landing speed
Drop a hammer and a feather side by side and the hammer wins easily — but only because of air. Take the air away (astronauts really did this on the Moon, and it's on video!) and they hit the ground at the exact same instant. For two thousand years people believed heavier things fall faster; Galileo showed they don't, and it's one of the most beautiful ideas in physics: near Earth, ignoring air resistance, every object falls with the same acceleration, regardless of its mass.
School Plan
Free Fall & Projectiles
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Related topics
Frequently asked questions
- Why are horizontal and vertical motion analyzed separately?
- Gravity acts only vertically, so it changes the vertical velocity while the horizontal velocity stays constant — the two are independent.
- What shape is a projectile’s path?
- A parabola, resulting from constant horizontal velocity combined with constant downward acceleration.