**Predicting Peak Height**

If aerodynamic drag and transient changes in pressure are neglected, a closed-form approximation for the peak height of a rocket fired vertically can be expressed as follows:

( = peak height reached, = Initial mass of water only, = Rocket mass with water, = Initial gauge pressure inside rocket, = density of water, = acceleration due to gravity) Assumptions for the above equation: (1) water is incompressible, (2) flow through the nozzle is uniform, (3) velocities are rectilinear, (4) density of water is much greater than density of air, (5) no viscosity effects, (6) steady flow, (7) velocity of the free surface of water is very small compared to the velocity of the nozzle, (8) air pressure remains constant until water runs out, (9) nozzle velocity remains constant until water runs out, and (10) there are no viscous-friction effects from the nozzle (see Moody chart).

Read more about this topic: Water Rocket

### Famous quotes containing the words height, predicting and/or peak:

“Much more frequent in Hollywood than the emergence of Cinderella is her sudden vanishing. At our party, even in those glowing days, the clock was always striking twelve for someone at the *height* of greatness; and there was never a prince to fetch her back to the happy scene.”

—Ben Hecht (1893–1964)

“All the critics who could not make their reputations by discovering you are hoping to make them by *predicting* hopefully your approaching impotence, failure and general drying up of natural juices. Not a one will wish you luck or hope that you will keep on writing unless you have political affiliations in which case these will rally around and speak of you and Homer, Balzac, Zola and Link Steffens.”

—Ernest Hemingway (1899–1961)

“In the mountains, the shortest way is from *peak* to *peak*: but for that you must have long legs. Aphorisms should be peaks: and those to whom they are addressed, great and lofty.”

—Friedrich Nietzsche (1844–1900)