ASTR 001 Lecture Notes - Lecture 5: Net Force, Hyperbola, Photon
Document Summary
Objects are weightless when in free fall. Laws of physics were the same laws of the universe. What are newton"s three laws of motion: object moves at constant velocity if no net force is acting, force = mass acceleration, for every force there is an equal and opposite reaction force. Conservation of energy: energy cannot be created or destroyed; it can only be transformed from one type to another. Energy comes in 3 basic types: kinetic, potential, radiative. Some subtypes important in astronomy: thermal energy, gravitational potential energy, mass-energy (e = mc2). What determines the strength of gravity: dire(cid:272)tl(cid:455) proportio(cid:374)al to the produ(cid:272)t of the masses (m x m, i(cid:374)(cid:448)ersel(cid:455) proportional to the square of the separation d. Ne(cid:449)to(cid:374)"s la(cid:449) of gra(cid:448)it(cid:455) allo(cid:449)s us to e(cid:454)te(cid:374)d kepler"s la(cid:449)s. Applies to other objects, not just planets. We can now measure the mass of other systems escape velocity -> object.
