The accompanying figure shows the velocity versus time curve for a rocket in outer space where the only significant force on the rocket is from its engines. It can be shown that the mass [math] (in slugs) of the rocket at time [math] seconds satisfies the equation [math] where [math] is the thrust (in lb) of the rocket’s engines and [math] is the velocity (in [math]) of the rocket. The thrust of the first stage of a Saturn V rocket is [math] lb. Use this value of [math] and the line segment in the figure to estimate the mass of the rocket at time [math].

(click to enlarge)