Question

A rock dropped from a bridge takes 3.21 seconds to hit the water. How high is the bridge in meters?

I need to find Vsub0 to be able to calculate h....but how do I get Vsub0???

Answer 1

is it -9.80 x 3.21= -31.458 is Vsub0??

Answer 2

h=151.47m??

Answer 3

the initial speed is zero. It was dropped, not thrown.

Answer 4

accck ok so

1/2(9.80)(3.21)^2= 50.5 m

Answer 5

(1/2)(9.81)(3.21)^2 = 50.5 meters

Answer 6

I'm learning slowly but surely!

Answer 7

more formally
h = Hi + Vi t - 4.9 t^2
0 = Hi + 0 - 4.9 t^2
Hi = 4.9 *3.21^2 = 50.5

Answer 8

yes, good