Answer:
a = G M / R^2 acceleration due to gravity
aE /aP = (ME / RE^2) / (MP / RP^2) = (ME / MP) * (RP^2 / RE^2)
Since MP = 2 ME and RP = 2 RE
aE / aP = 1/2 * 2^2 = 2
So the gravitational field strength of the planet is 1/2 that of the earth or 4.9 N/kg