Multnomah falls in oregon are approximately 206m high. if the columbia river is flowing horizontally at 2.90m/s just before going over the falls, what is the overall velocity of the water when it hits the bottom?

63.6 m/s

Explanation:

The motion of the water inside the waterfall is the motion of the projectile, so it has:

- a horizontal velocity which is constant: , since there are no forces acting along the horizontal direction

- a vertical motion which is an accelerated motion with constant acceleration, g=9.8 m/s^2, due to the effect of the force of gravity

The magnitude of the vertical velocity of the water when it hits the ground can be found by using

where

vy is the final velocity

uy=0 is the initial velocity

h = 206 m is the height of the waterfall

Solving for vy,

so this is the vertical velocity of the  water as it hits the ground.

The magnitude of the overall velocity will be the resultant of the horizontal and the vertical components: