How long will it take the rock to hit the ground ?

Question

Chuck drops a rock from a height of 70 m.

How long will it take the rock to hit the ground?

h (t) - -4.9t^2 + vt +h where v is the initial velociry and hi is the intial height.

Round to the nearest tenth of a second.

Answer 1

h(t) = -4.9t² + vt + h

h = 70 m

v (initial velocity) = 0

h(t) = 0 at ground level

0 = -4.9t² + (0)t + 70

4.9t² = 70

t² = 14.28

t = 3.8 sec.