Newton’s Law of Gravitation
•For the gravitational attraction due to a hollow shell or
uniform sphere:
–The force is the same as that of a point source of the same
mass located at the center of the sphere
–This is true only outside the sphere.
•At the center, the gravitational force must be zero (vectors all cancel
due to symmetry)
Because Earth is approximately
spherically symmetrical (recall this from
the seismology chapter?), we can treat
the Earth as a point source of mass
located at the center of the Earth!
Docsity.com
