a rock is dropped off a bridge. How fast is it moving when it hits the water 2.5s later?

To find out how fast the rock is moving when it hits the water after 2.5 seconds, we can use the equations of motion to calculate its velocity.

First, we need to know the acceleration due to gravity, which is approximately 9.8 meters per second squared (m/s^2) on Earth. Since the rock is being dropped, we assume it falls freely without any other forces acting on it.

Using the equation of motion:

v = u + at,

where:
v = final velocity
u = initial velocity (which is zero since the rock is initially at rest)
a = acceleration (in this case, acceleration due to gravity)
t = time

Plugging in the given values:

v = 0 + (9.8 m/s^2) * 2.5 s

v = 24.5 m/s

Therefore, when the rock hits the water after 2.5 seconds, it will be moving at approximately 24.5 meters per second.

V = g t, where g is the acceleration of gravity.

You should get 24.5 meter/second.

(about 55 mph)