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2. Earth’s Gravitational Field g is also called the gravitational field strength Units: N/kg N. BAJAJ

3. Geocentric Model: Ptolemy Heliocentric Model: Copernicus Tychonic Model: Tycho Brahe Kepler’s Elliptical Model

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8. http://www.youtube.com/watch?v=d__hN6nqi-k http://www.youtube.com/watch?v=mbDQSxUXef k http://www.youtube.com/watch?v=54MSV2B399o &feature=related

9. N. BAJAJ Near Earth’s surface: However, a few hundred kilometers above the surface of Earth, why does this equation become inaccurate? the ‘g’ value starts decreasing Therefore, a general way of determining the E g must be found out

10. N. BAJAJ Remember, the law of universal gravitation: In order to increase the separation between two masses such as these, work must be done The force required to increase the separation between these two masses looks like this:

11. N. BAJAJ How are force, distance, and work related? How can work be found from this Force-Distance graph? Area under the graph (N.m) Rearrange the equation: Therefore: E 2 = Therefore: E 1 =

12. N. BAJAJ Illustration of Earth’s Potential Well

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14. Rocket at rest on Earth: E T = E g Rocket in flight E T = E k +E g Rocket reaches zero velocity at maximum height E T = E g Therefore, E T <0 and it is earth-bound

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18. On Earth’s surfaceIn Earth’s Orbit

19. N. BAJAJ In Earth’s OrbitOn Earth’s surface IS EQUAL TO