Mathematics for IGCSE & O level - Proportion (Section 1 - No. 39)
The force of gravity between two objects is inversely proportional to the square of the distance between them. If the distance between two objects is increased by a factor of 3, the gravitational force between them will be:
1/9 of the original force
1/3 of the original force
3 times the original force
9 times the original force
توضیح
Gravitational force = k / d^2, if d becomes 3d, new force = k / (3d)^2 = k / 9d^2, which is 1/9 of original force