Question

two identical pellet guns are fired simultaneously from the edge of a cliff. these guns impart an initial speed of 30.0 m/sec to each pellet. gun a is fired straight upward, with the pellet going up and then falling back down, eventually hitting the ground beneath the cliff. gun b is fired straight downward. in the absence of air resistance, how long after pellet b hits the ground does pellet a hit the ground?

Answer 1

t = (v2 - v1) / a = (0 - 30.0) / -9.80 = 3.06 sec time to reach top In 2 * 3.06 = 6.12 sec it will be back where it started with a speed of 30.0 m/s downward

Pellet a is 6.12 sec behind pellet b