(originally provided by @chschu, converted to Markdown with LaTeX math by @kajott)
Variables used here:
-
$\overrightarrow{p_i}$ = initial position of hailstone number i [known] -
$\overrightarrow{v_i}$ = velocity of hailstone number i [known] -
$t_i$ = time of collision between the rock and hailstone number i [unknown] -
$\overrightarrow{p_R}$ = initial position of the rock [unknown] -
$\overrightarrow{v_R}$ = velocity of the rock [unknown]