Two cannons (at different height) aim at each other.
What will happen if both cannon fire at the same time?
Want to know the answer? Just press the start button

You can change the position of cannons
  1. Left cannon:  Left click at the blue dot and drag it up and down.

  2. right cannon: Right click at lower right corner and drag it left and right

  3. Both of them will adjust angle to aim at each other.

You can change the initial velocity of cannonball
click the red arrow and drag it left/right or up/down.

The length of the red arrow is represent the displacement of cannonball

in one second (under no gravity)

??? As long as the velocity is large enough,

the cannonball will hit each other!!!

Click the right mouse button to continue.
If the difference in height is h, horizontal distance is w,
What is the requirement for the velocity v1,v2?

Want to know the reason? Select showcheckbox
    to show the trajectory of both cannonball when there is no gravity,
    and the effect of the gravity to the cannonball(yellow line).

How to pause the animation

  1. Press the left mouse button to pause, release it to continue

  2. If you click the right mouse button, you need to click it again to continue.

  3. What if you click right mouse button, then press the left mouse button?

    1. Try it! You will know the answer.