INTO the NEXT DIMENSION (2-D Motion)
The main challenge in teaching projectile motion is demonstrating the independence of motion along each axis. These demonstrations will focus primarily on that.
15. Vertical Toss, Horizontal Motion |
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| In this demonstration, we will drop a ball straight to the ground while walking with it. Students will be able to see the ball follow the vertical line of the person’s body, but will also see the ball follow a parabolic shape. The dropped motion imparts nothing to the ball to have it move forward, which means the person’s walking motion independently imparts horizontal motion to the ball. | |
16. Slug Gun |
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 In this demonstration, two balls will begin at the same height on a launcher. On one side, the ball will be dropped, on the other, it will be fired horizontally. Both balls will strike the ground at the same time, as observed by students listening for the balls to hit metal plates on the floor. This is because vertically their ball’s motions were identical. |
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17. Stop Motion Ping Pong Balls |
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 We have created a visual to pair with projectile motion that will show (in essence) the stop motion progression of a projectile. By changing the angle of the launch axis, students can see how the ball might go higher or farther depending upon that angle. A ball will then be launched to show that this actually works in real time.
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18. “Monkey-Hunter” Problem |
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 In this demonstration of a classic physics problem, a hunter struggles with where to aim their weapon. Aiming at a creature on a branch, the creature will release the branch the instant the weapon is fired, causing the creature to fall towards the ground. Where should the hunter aim? In the previous two demonstrations, it was showed that projectiles will move away from the axis of launch under the independent, vertical influence of gravity. If the hunter aims directly at the creature, then it, too, will be moving away from the axis of launch under the independent, vertical influence of gravity. So, the hunter should aim directly at the creature, and the projectile and creature will meet, as they are both in free fall. |
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