Projectile Motion

Freefall/Projectile Motion is just an application of kinematics equations to more realistic scenarios. However, there are some important distinguishing features of freefall/projectile motion to make. ​

1) Vertically, the acceleration, unless otherwise stated, is -9.8 meters/(seconds squared)

2)Horizontally, the acceleration, unless otherwise stated, is 0 meters/(second squared) which means the horizontal velocity of projectiles in freefall don't change.

3) If you know the time it takes for an object to move a certain displacement in one direction, you know the time it takes for the other direction.

​ Because of what is shown here on the diagram above, it is important to always split up motion into its horizontal and vertical components. Given the angle theta shown in the diagram, we can split the ball's velocity into vcos(theta) for horizontal motion and vsin(theta) for vertical motion. We can use Pythagorean theorem to find the total velocity as mentioned here. If one can do this, along with remembering the 3 rules above applied to kinematics equations, you can effectively solve the large majority of projectile motion equations in physics.

You may be wondering about a caveat of projectile motion. If I'm on a planet, say Earth, and I throw a projectile upwards at a slight angle such that it travels horizontally. If the object lands in front or behind me, wouldn't its displacement be slightly greater in magnitude because of the Earth's curvature? Well, technically yes. However, the Earth's curvature is so negligibly small for everyday distance that you can simply not account for it.