1. *Turn off the air resistance*. Making sure you change only **one**
variable (ie. initial velocity) at a time, try to get some projectiles
to hit the traget (at a range of 100 meters). Before firing each projectile, try to predict the range using:

where v_{o} is the launch speed,
is the launch angle
(from horizontal), and g is the gravitational acceleration (9.8
meters/second^{2}).

Does your computed range match the one on screen?
The final range you achieved appears on the status line at the bottom of your browser. (**NOTE:** Do not adjust the launch height).

2. Next, *turn on the air resistance* and vary the terminal velocity.
Use the equation above to compute the expected range (without air
resistance). Compare the expected range to the observed range. Explain why
they are different.

3. *Turn off the air resistance again*. Now vary
gravity and compare the trajectories (this is obviously something you
could not do on earth, at least easily).

4. Now, *turn on the air resistance one last time*. Vary
**only** the time step in incriments of 0.2
until you get to a time step of 1. What do you notice?

The time step is the incriment over which
the equations are calculated. The smaller the time step the smoother,
and more accurate the simulation. Of course, using smaller time steps
also means **many** more calculations. If you had to do this by hand
it would take a very long time, good thing you have a computer close
by.