1. Universal Gravitation & Satellites
Textbook: 3.3 & 3.4
Homework: pg. 141 # 3, 5
pg. 143 # 9, 11, 12
pg. 147 #2

2. Universal Gravitation
Gravity is the mutual force of attraction between any two objects that contain matter, regardless of their size.
The strength of the gravitational force between two objects depends on two variables: mass and distance.

3. The Law of Universal Gravitation
Universal Gravitational Constant,
Mass of object 1, m1
Mass of object 2, m2
Distance between the centres of the object, r
Examples:
Pg 141 # 4
Pg 144 # 5b

4. Satellites and Space Stations
Any object that is orbiting Earth is undergoing constant free fall toward Earth
Therefore,
Minimum orbiting speed:

5. Ex. 1: The ISS travels at an altitude of 450 km above the surface of the Earth.
Ex. 2: How fast must you run to be able to hover above the surface of Earth? 7.9x103m/s
(b) How many times will the astronaut circle the Earth in 1 hour?
(a) Determine the gravitational force on a 64 kg astronaut at that altitude.

6. Apparent Weight and Artificial Gravity
Apparent weight: is the contact force exerted on an accelerating object in its non-inertial frame of reference.
Artificial gravity: where the apparent weight of an object is similar to its weight on Earth