For any projectile launched horizontally, the projectile is given an initial horizontal velocity. The cannonball will also accelerate horizontally due to free fall. The goal of this lesson is to show you the trajectory of the cannonball.
For, example, let's say that you launch a cannonball horizontally as shown in the picture above.
Once the cannonball is in the air, there are two things happening with the cannonball at the same time.
The cannonball will be affected by the horizontal speed and the vertical speed.
First, let us talk about the horizontal speed. Notice that there is no horizontal acceleration because there is no
horizontal force acting on the cannonball . With no horizontal
acceleration, the cannonball will move horizontally with constant
Below, we show constant velocity for the cannonball by using vectors that have the same size.
Second, as the cannonball move horizontally, gravity will force the cannonball to fall vertically as well. Therefore, the cannonball will experience free fall. We saw in the lesson about free fall that objects in free fall accelerate.
This means that the speed is not
constant, but keep on increasing. Since the speed is increasing, the
object will cover a greater distance in each successive equal time
interval. Below, we show a speed that is increasing as the cannonball experiences free fall.
We can combine the vertical and horizontal movement/speed of the
cannonball to see what we end up with. See below the horizontal speed,
the vertical speed, and the resultant speed in red. The ball move along
the green curve which is a parabola. The vectors shown in red (resultant
speeds) are tangent to the green curve although it does not look
The path traced above in green is the path that a projectile will follow when the following conditions are met.
Next, we learn about the path and speed of a projectile launched at an angle.
This projectile launched horizontally quiz will help you see how the
velocity and acceleration behave when the projectile is launched
horizontally. You will not need to use a paper and pencil to complete
First, read the lesson about projectile launched horizontally and then take this quiz.
Objective of the quiz: