3
Three.
3 points which do not all lie on the same line.
3
Three
Two. Two points determine a line. Three points determine a plane.
3
The minimum is two points, one point at each end of the line.
3
three
Three.
3 points which do not all lie on the same line.
3
Three
2 points
A minimum of 6 sets of data are needed to make a valid conclusion.
The answer depends on the sort of trajectory. If it isthe trajectory of a projectile, affected only by gravity then 3 points are enough. As soon as you add other forces: such a drag or continued propulsion, the number of points required increases.