Question

In the 2nd lab you were studying water squirting out from a hole in a cylinder filled with water into a tub. Just as a falling ball converts potential energy to kinetic energy, water pressure pushed water out of the hole by converting potential energy per unit volume (density x g x height) to kinetic energy per unit volume (density x velocity^2/2). Assume you have a 20 cm head of water above the hole and that the hole is 40 cm above ground.

How will the water reach by the time it touches the ground (in cm)?

Answer 1

If the hole is 40 cm above ground, then the water will reach a height of 20 cm by the time it touches the ground. This is because the water's potential energy per unit volume (density x g x height) is converted to kinetic energy per unit volume (density x velocity2/2) as it moves out of the hole and falls towards the ground. By the time it reaches the ground, it will have lost all of its potential energy, and thus, have no kinetic energy left, resulting in a height of 20 cm.