A) Let R and M be the radius and mass of the earth respectively. We saw in class that the speed of an object in low earth orbit is √(GM/R). We also saw that a satellite in a geosynchronous orbit is further away from the earth than satellites in low earth orbits. Which of the following can we infer about the launch speed of the geosynchronous satellite (assuming no thrust)?
Select one:
a. The launch speed is greater than √(2GM/R)
b. The launch speed is equal to √(2GM/R)
c. The launch speed is equal to √(GM/R)
d. The launch speed is greater than √(GM/R) but is smaller than √(2GM/R)
B) When an asteroid collides with a planet, the debris from the collision has a chance of getting blasted off the planet and landing on another planet. Which of the following is correct?
Select one:
a. It is easier for the debris to get blasted off Mars and land on Earth
b. The likelihood for the debris to go either way is the same
c. It is easier for the debris to get blasted off the Earth and land on Mars
d. The likelihood depends on the details of the collision and we cannot make a general statement
C) What is a black hole's event horizon as described by general relativity?
Select one:
a. a sphere on which light orbits in a circle
b. A boundary where any infalling object burns up
c. A boundary of no escape
d. A region with nearly infinite density