Question

Dylan and Sophia are walking along a bluebird lake on a perfectly calm day. Dylan, determined to impress Sophia by his ability to skip rocks, picks up a completely horizontal velocity of 7.0 m/s from a height of 4.1 m above the water surface. How far from the edge of the water does the rock travel before it makes its first skip.

Answer 1

First we need to find the time in the air
d = 1/2gt^2 + vt
Since there is no inital vertical velocity
4.1 = 1/2 (9.8) t^2
8.2/9.8 = t^2
0.8367 = t^2
t = 0.9147s

Now we multiply by speed
7m/s x 0.9147s = 6.4m