Orbits, Tides, and the Acceleration of Gravity Flashcards
What is total orbital energy?
Gravitational + kinetic energy. It stays constant if there is no external force
Can orbits change spontaneously?
No
What can make an object gain or lose orbital energy?
Friction, atmospheric drag, or a gravitational encounter
What might happen if an object gains enough orbital energy?
It may escape (change from a bound to an unbound orbit). Escape velocity from earth is about 11 km/s from sea level
How does gravity cause tides?
Moons gravity pulls harder on near side of the earth. Difference in moons gravitational pull stretches earth
What is tidal friction?
Gradually slows earths rotation and makes the moon get farther from earth. The moon once orbitted at either a faster or slower speed, but tidal friction caused it to lock in synchronous rotation
How do you change an orbit?
Change in total energy
Why do all objects fall at the same rate?
Mass of object in Newtons second law cancels out mass in law of gravitation
