EntityQ5499609· pop 8· linked from 12 articlesFree-fall timeSign in to saveConcept in astrophysicsConnectionsIsaac NewtonPersontimeEntitygravityEntityInternational Standard Book NumberEntityInternational System of UnitsEntitysupernovaEntityKepler's laws of planetary motionEntityfree fallEntitycenter of massEntityorbital eccentricityEntitystar formationEntitydivergence theoremEntityhelioseismologyEntityelliptic orbitEntityparabolic trajectoryEntitycircular orbitEntitysemi-axisEntitytest particleEntitypoint sourceEntityRadial trajectoryEntityCategoriesCelestial mechanicsFalling