That's a good applet on the top post
May i suggest some refinements.
idea from 1
Likes: can allow for exploring different angles
air resistance variable for more realistic simulation?
step back < button
Dislikes: need a auto scale button for those angles and velocity where collision is outside current frame
idea from 2
Likes: the slider with editable fields for duo inputs, can Ejs do this easily? i did raise a feature request on Paco's wiki
but no news yet.
field to change acceleration in the y direction, this is important for inquiry learning
the vector checkbox for velocity visualization
graph of vx vy of both ball and monkey to allow of comparison of the significance of vy
on a graph paper grid to allow for calculation of the angle instead of trial and error.
Dislikes: burning monkey, bad idea
idea 3 no links because it is a commercial tool ( you can find by googling "shoot monkey" )
Likes: basketballer(instead of monkey) hanging on a tree, release hand from tree and fall, catch the ball, the morale story is sport related instead of shooting a monkey which is more suitable for promoting animal loving society that this resource can help. but a toy monkey should be fine.
Likes: laser pointer to illustrate the straight line path instead of a line drawn, more realistic if can show how it is achieve in real life