Mathematics for IGCSE & O level - Proportion (Section 2 - No. 9)
The force of gravity between two objects varies inversely as the square of the distance between them. If the distance is doubled, by what factor does the force change?
1/4
1/2
2
4
Explication
F = k/d^2. If d becomes 2d, then force = k/(2d)^2 = k/4d^2 = Force/4. The force becomes 1/4