Question

Heather and Jerry are standing on a bridge 51 m above a river. Heather throws a rock straight down with a speed of 17 m/s . Jerry, at exactly the same instant of time, throws a rock straight up with the same speed. Ignore air resistance.
How much time elapses between the first splash and the second splash?

Answer 1

h=vi*t-4.9t^2
solve for t, given vi=+17, then vi=-17
h=-51