Final answer:
The gravitational force on an object of mass 2m at an altitude of the moon's radius above its surface is one-fourth of the gravitational force it would experience on the moon's surface, according to Newton's universal law of gravitation.
Step-by-step explanation:
To find the gravitational force of attraction to the moon on an object of mass 2m at an altitude equal to the moon's radius, r, above the surface of the moon, we can use Newton's universal law of gravitation, which states that the force between two masses is directly proportional to the product of their masses and inversely proportional to the square of the distance between their centres:
F = G(Mm)/r^2
Here, G is the gravitational constant, M is the mass of the moon, m is the mass of the object, and r is the distance from the object to the centre of the moon. Since the object is at an altitude of r, the total distance between the object and the moon's centre is 2r. Plugging in the values:
F = G(2Mm)/(2r)^2
F = G(Mm)/2r^2
This equation shows that the force of attraction on the object is one-fourth of the force it would experience on the surface of the moon.