افتح حساباً مجانياً لبدء المنهج كاملاً والدروس التفاعلية — يعمل Google أو رقم الهاتف المحمول.
Force between two masses ∝ product of masses, inverse square of distance.
Stored energy between two masses — zero at infinity, negative at finite separation.
Speed at which gravity exactly provides the centripetal force.
Three laws of planetary orbits — ellipse, equal areas, T² ∝ a³.
Minimum launch speed that lets an object escape gravity forever.