A projectile's motion is described by the equations

x = -50t cos 30° + 400
y = -81t2 + 50t sin 30° + 700
a. Is this projectile motion occurring on Earth, the Moon, or Mars? What are the units used in the problem? (Hint: Look for the value of g.)
b. What is the initial position? Include units in your answer.
c. At time t = 0, what direction is the projectile moving? (up, up-right, right, down-right, down, down-left, left, or up-left)
d. What is the initial velocity? Include units.

n dog and disc competitions, the Frisbee is one projectile (although it does face wind resistance) and the dog is another. Each object has a horizontal and vertical component to its motion.