Normally you find projectile in ideal case, i.e. without any air drag.
The following applet add airdrag to simulate more realistic case.
Drag Force is proportional to F = -kV2
Mass of the object is assumed to be 1kg.
If the mass of the object is different, you should divide k by real mass k->k/m .
Normally, the drag force is very small for small projectile motion in air.
So the initial velocity was set to 626 m/s (very large value) and the number display for distance was always in unit of km, so that the air drag effect can be visible more easily.
The right most text field (initial value=100) is used for scaling the X-Y coordinate.
For example: You want to have a smaller initial velocity v=62.6 m/s.
You might want to change the sclae from 100. to 1. (The same trajectory will be displayed for v=626m/s and scale=100.)
If you want to have smaller velocity, i.e. v=20 m/s , you might want to change scale to 0.1