Re: How can I best investigate velocity versus gravity

I teach high-school physics, and for two years I also home schooled my son, and we have actually done the experiment you propose. It works!! The apparatus can be simple, although you can make it as complicated as you want to.

The idea, as you know, is to launch one of the projectiles sideways at exactly the same time that you let go of the other projectile so it can fall straight down. Here is a simple apparatus that can do the trick:
1) Attach to a base a meter stick (or a yard stick!) at one end so it can pivot. This can be done by drilling a hole through the end of the stick and putting a screw through the hole into the base. This pivot will be at the end away from where the projectiles are launched.
2) At the other end of the stick, where the projectiles will be launched, attach a block (wood will do, but so will metal) to the base, about 3 to 4 inches toward the pivot from this end of the stick. This block acts as a stop against which the stick hits to stop its motion.
3) Attach to the stick, on the top surface, at the launching end, a block of wood (or metal) that has two places for projectiles. One place will be flat, and the other place will be in the form of of an "L". The idea is that, when the stick is hit (with a hammer or another stick) from the side, one projectile will be launched sideways by the vertical part of the "L", and the other projectile will slip off the flat place and fall straight down (more or less).

Okay, now you have the apparatus. Place the launching end of the stick about an inch away from the stop block, and put the two projectiles in place. Sharply hit the stick toward the stop block with another stick or a hammer. When you do this the projectiles should be launched as desired. There will be a small delay between when the "straight down" projectile is dropped and when the "sideways" projectile is launched, but the delay will be small if you hit the stick sharply enough. Also, if the "sideways" projectile is launched a little bit up or down you may have to slightly alter the shape of the "L" to compensate.

Have a good time with your project!

John Link, MadSci Physicist