Planet krypton has 2 times the radius and 2 times the mass of the earth. what is the best estimate for the magnitude of the gravitational field at the surface of planet krypton in m/s2?
a. 20m/s^2
b. 10m/s^2
c. 5m/s^2
d. 2.5m/s^2

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  C.  5 m/s^2

Step-by-step explanation:

The force due to gravity is proportional to the mass and inversely proportional to the square of the radius. So, Krypton's gravity in relation to Earth's is ...

  (2)/(2^2) = 1/2

Earth's surface acceleration due to gravity is about 10 m/s^2, so 1/2 that is about 5 m/s^2. (Choice C)