A newly discovered planet 581c, has a mass 5 times that of the Earth's mass and a diameter one and a half that of the Earth.If the Earth's...

For a mass m on Earth, the acceleration due to the
gravitational force of attraction is m*g = G*Me*m/r^2, where G is the gravitational
constant, Me is the mass of the Earth, and r is the radius of the
Earth.

For planet 581c, the mass is 5 times that of the
Earth and the diameter is 1.5 times that of the Earth.

A
mass m, on the surface of the planet would experience an acceleration due to the gravity
of the planet given by:

m*gx =
G*5*Me*m/(1.5*r)^2

=> gx =
G*5*Me/(1.5*r)^2

we have g =
G*Me/r^2

=> gx =
[5/(1.5)^2]*G*Me/r^2

=> gx =
5/(1.5)^2*9.81

=> gx = 21.8
m/s^2

The planet's gravitational field
strength is 21.8 N/kg