Chronology Current Month Current Thread Current Date
[Year List] [Month List (current year)] [Date Index] [Thread Index] [Thread Prev] [Thread Next] [Date Prev] [Date Next]

rocket motion



Gang:

Do you like solving already solved problems? Sometimes
they are fun. I made two assumptions about rocket
motion; (a) the rocket throws out mass linearly; and (b)
the relative velocity of the rocket with respect to the
exhaust is constant. If we let v be the relative velocity
of the rocket with respect to the exhaust, m be the
initial mass of the rocket and fuel, and a be the rate at
which the mass of rocket and fuel decreases; then we can
calculate the distance the rocket has moved with reference
to some origin in outer space with respect to a time
parameter.

My result is:

x(t) = (mv/a){(1 - at/m)ln(1 - at/m) + at/m}

Apparently, its speed continues to increase as long as the
rocket motors will continue throwing out the mass so that
the relative velocity is constant and the decrease of the
mass of the rocket-fuel part of the system is linear. WBN
Barlow Newbolt
Department of Physics and Engineering
Washington and Lee University
Lexington, VA 24450

Young man if I could remember the names of all of
these particles I would have become a botanist
Enrico Fermi
Telephone and Phone Mail: 540-463-8881
Fax: 540-463-8884
e-mail: NewboltW@madison.acad.wlu.edu