1. Two solid spheres of radius R made of the same type of

Last updated: 7/10/2022

1. Two solid spheres of radius R made of the same type of steel are placed in contact, as shown in the figures above. The magnitude of the gravitational force that they exert on each other is F₁. When two other solid spheres of radius 3R made of this steel are placed in contact, what is the magnitude of the gravitational force that they exert on each other? (A) F1 (B) 3F1 (C) 9F1 (D) 81F1