A rock falls off a bridge and hits the water 8 seconds later. How high is the bridge?

1 Answer
Jun 29, 2016

It is 313.92 m.

Explanation:

The dynamics of a free fall body is regulated by the constant acceleration motion.
The equation of motion says that

s=1/2gt^2

where s is the space traveled, g=9.81 "m"/"s"^2 is the acceleration of gravity and t is the time.
Then the space traveled is

s=1/2*9.81 "m"/"s"^2*8^2"s"^2

=32*9.81 "m"=313.92 "m".