Spherical planet A has mass m and radius r. Spherical planet B has mass and  radius 2r. How does the gravitational field strength at the surface of planet B compare to the gravitational field
strength at the surface of planet A?
a) It is the same as planet A
b) It is twice that of planet A
c) It is half that of planet A
d) It is one-eighth that of planet A
Spherical planet B has mass (?????) and  radius 2r.
the mass is m/2, or b.
what will be the answer?
To compare the gravitational field strength at the surface of planet B to the gravitational field strength at the surface of planet A, we can use the equation for gravitational field strength:
g = G * (M / R^2)
where g is the gravitational field strength, G is the gravitational constant, M is the mass of the planet, and R is the radius of the planet.
Let's first find the expression for the gravitational field strength at the surface of planet A:
g_A = G * (m / r^2)
Now, let's find the expression for the gravitational field strength at the surface of planet B:
g_B = G * (M / (2r)^2)
Simplifying the expression for the radius of planet B, we get:
g_B = G * (M / 4r^2) = (1/4) * G * (M / r^2)
So, the gravitational field strength at the surface of planet B is one-fourth (1/4) of the gravitational field strength at the surface of planet A.
Therefore, the correct answer is (d) It is one-eighth (1/4) that of planet A.