Click on the picture field below. Click on the radio buttons to change the x- and y-accelerations, then click on the picture again to see fireworks with a new acceleration.
See the notes below.
This animation demonstrates projectile motion with no air resistance using various accelerations in the x and y directions.
The buttons at the bottom control the x-acceleration. The button between the square brackets marks zero x-acceleration. Buttons to the left of zero represent increasing negative x-accelerations. Buttons to the right represent increasing positive x-accelerations.
Negative x-accelerations point to the left. Positive x-accelerations point to the right.
The buttons on the right side control the y-acceleration. They work much like the x-acceleration buttons with positive upward pointing y-accelerations increasing above the zero marker and negative downward pointing y-accelerations becoming bigger below the zero marker.
To demonstrate normal projectile motion, set the x-acceleration to zero, since gravity does not pull horizontally, and set the y-acceleration to some negative value.
To demonstrate motion without gravity, set both x- and y-accelerations to zero. Of course, you will get fireworks with straight trajectories.
Negative gravity could be simulated with zero x-acceleration and a positive y-acceleration.
Isaac Newton's laws of motion explain that accelerations are caused by forces. The direction of the acceleration is in the same direction as the force which is causing it. The acceleration and the force both point in the same direction.
One could, therefore, imagine the radio buttons to be controlling the direction of the force on the fireworks. One could think of this as if there were no gravity; however, a wind was blowing. The radio buttons control the direction of the wind. The firework would be pushed from the wind accordingly.
One could further imagine the above area to be a controllable constant force field through which a batch of effected particles is randomly thrown.