Welcome to My Planet!

     The French author Antoine de Saint-Exupery tells us that the Little Prince could walk around his planet in about one hour. Assuming the Prince walked at a normal rate, the radius of his planet must have been about 1 km. The story implies the Prince's weight was normal, which means that the value of "g" on his planet was the same as on Earth (about 10 m/s2). What is the mass of this tiny planet? 

     The Prince's mass is 40 kg and he weighs 400 N. Remember that G = 6.67 x 10-11 N-m2/kg2. (Bonus... what is the planet's density?)

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