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In Scratch, the Trajectory formula is used for projects such as:

  • Rocket or baseball simulators
  • Tank games
  • Anything that includes the curve of a projectile

The formula(e) calculate(s) where on the screen the projectile should be. As well as calculating this, there are many other formulae that calculate different things

These are the formulae:

Horizontal velocity: v°x = v°cos(ß)
Horizontal distance: x = a+v°xt
Vertical velocity: v°y = v°sin(ß)-gt
Vertical distance: y = b+v°sin(ß)-0.5gt²

v° is the initial velocity, ß is the projectile angle (from -90 to 90), a & b are the starting coordinates, g is the informal gravity constant 9.81, and t is the time since the launch.

Other Formulae

Maximum height: H = b+[v°²sin²(ß)]/[2g]
Horizontal range: R = [v°²sin2(ß)]/[g]-a

sin(ß) and cos(ß) are the vertical and horizontal components (or velocities).

See Also