8. Science Fiction?
• "The Force is what gives a Jedi his power. It's an
energy field created by all living things. It
surrounds us and penetrates us. It binds the
galaxy together.“
• https://www.youtube.com/watch?v=MTY1Kje0yL
g
• Truth: Gravity is an energy field; It surrounds us
and binds the OBJECTS in the UNIVERSE together.
It is a force. Just not THE force. And it is with us.
10. Example Problems: Finding g on any
planet.
• g = Gm/r2
• What is the acceleration of gravity on Earth?
• G = 6.67e-11
• mearth = 5.98e24 kg
• earth radius = 6400e3m
• g = 6.67e-11 * 5.98e24/(6400e3)2
• g = 9.8 m/s2
11. Way to find the mass of the earth.
• g = 9.8 m/s2 was already known, Newton
could calculate G = 6.67e-11, and the radius of
the earth was
already known.
So with those values
scientists were able
to calculate the
mass of the earth.
12. Find the mass of Mars:
• g = 3.5 m/s2 on the surface.
• radius of Mars = 3390 km or 3390e3 m
G = 6.67e-11
3.5 = 6.67e-11 * m/(3390e3)2
Solve for m
(3.5 * 3390e3)2/6.67e-11 = m