*A common basis for comparing rocket fuel systems is the specific impulse, defined as lbf of thrust produced divided by lbm/s of fuel and oxidizer consumed. The common values are 250 to 400 lbf · s/lbm. We frequently see the specific impulse referred to simply as “300 s.” Is 300 s the same thing as 300 lbf s/lbm? European engineers regularly express the same quantity in terms of the equivalent exhaust velocity of the rocket. If a rocket has a specific impulse of 300 lbf s/lbm, what is its equivalent exhaust velocity?