Projectile Motion
A projectile has constant horizontal velocity and accelerates down vertically.
About this topic
A projectile moves under gravity after launch. Its horizontal and vertical motions are independent: horizontally it travels at constant velocity, vertically it accelerates down at g. The path is a parabola.
Splitting the initial velocity into components lets you find time of flight, maximum height and range. With launch speed v at angle θ, the horizontal component is v cos θ and the vertical component is v sin θ. The vertical motion decides how long the projectile is in the air, and the horizontal speed then gives the range.
Example: a ball is kicked at 20 m/s at 30 degrees. The vertical speed is 10 m/s, so it rises for about 1 s and lands after about 2 s. The horizontal speed is about 17.3 m/s, so the range is about 35 m. Maximum range on level ground occurs at 45 degrees, ignoring air resistance. Athletes in javelin, basketball and golf use these ideas, and so do engineers aiming water jets.
Common misconceptions: there is no horizontal force after launch in the ideal case, and at the top of the path the velocity is not zero, only its vertical part is. A ball dropped and a ball fired horizontally from the same height land at the same time.
Key ideas
- Horizontal and vertical motions are independent
- Range is maximal at 45°
- The path is a parabola
Quick check
Use cases: where Projectile Motion helps
- Homework: review the key idea behind Projectile Motion before you start a problem set.
- Exam revision: use the quick check to test whether you can recall Projectile Motion without notes.
- Visual learning: play with the interactive lab to see how Projectile Motion changes when you adjust its inputs.
- Teaching a friend: explain Projectile Motion in your own words, then compare your version with the key ideas.
The same laws describe car crashes, sports, satellites and everyday machines.
Frequently asked questions
What is Projectile Motion?
A projectile has constant horizontal velocity and accelerates down vertically.
What will I learn in Projectile Motion?
Horizontal and vertical motions are independent. Range is maximal at 45°. The path is a parabola.
Is Projectile Motion part of Physics?
Yes. It is one of 150 Physics topics on LearnViz HighSchoolEdu, with 3 key ideas, a live animation and a quick check.
Does the Projectile Motion lab work on a phone or tablet?
Yes. The animation resizes to fit your screen and supports touch, so you can drag, tap and slide with your finger.
How should I study Projectile Motion?
Read the summary and key ideas first, play with the interactive lab to see the idea in motion, then answer the quick check. If you get a question wrong, go back to the key idea it tests.
Do I need an account, and is my progress saved?
No account is needed. Marking a topic as learned is saved in your own browser, so it stays on that device and is not sent to a server.