Talk:A bug in my high school physics intuition

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Rocket ships are weirder than bicycles most of the energy you expend in accellerating isn't your kinetic energy, but the kinetic energy of your propellant: $E = p^2 / 2m$, $p^2$ is the same for the rocket and the propellant, but pointing oppositely, and for small thrust the propellant mass is much smaller. (For things like orbital inserters, this isn't true anymore; one needs Tsiolkovski's rocket equation; [[1]] e.g.). On a bicyle, your "propellant" is actually the earth, which means most of the energy expense *is* your own kinetic energy (because the earth is much heavier than you)

Hope that was amusing, jesse 174.116.253.167 16:09, 23 September 2014 (PDT)