Horizontal Projectile Motion Math
Create a Separate X and Y Givens List
Horizontal projectile motion math problems start with an object in the air beginning with only horizontal velocity. These problems often start with an object rolled off a table, being thrown horizontally, or dropped by a plane.
When we approach horizontal projectile motion problems separating the x and y components and work through problems keeping those givens separate.
When you see a problem with an object in the air traveling going forward but under the influence of gravity, create a separate X and Y givens list.
Projectile Motion Equations
Look at the equations used in projectile motion below. In the X axis you will only use our constant motion equation. Below you will see vx which is just velocity in the x axis.
In the Y axis you will use our common acceleration equations. Below they are just specialized for something in the air. Our normal variable a (acceleration) is exchanged for g (acceleration due to gravity). X is exchanged for Y since the object will be moving in the Y axis. Also the vi and vf are replaced with viy and vfy just representing that the velocities are only Y axis components.
Horizontal projectile motion problems will have separate X and Y givens with only time being in both givens list. Projectile motion problems end when the object hits the ground. At that moment the projectile is done going forward and falling.
Two ways to find time:
- If you have the Y displacement you can find time using Y axis givens. Don't forget that viy = 0 m/s and g = 0 m/s2
- If you have horizontal velocity (vx) and X axis displacement (X), you can find time in this axis
Joe throws a ball 9.4 m/s horizontally forward from the second floor 6 meters off the ground, how far downrange does it land?
A ball rolls off a table at 3.0 m/s and lands 2.5 meters away. How high was the table?
Horizontal Projectile Motion Math Quiz