By approximate relative strength, which of the four basic forces is the weakest?

1. The four basic forces are ranked by approximate relative strength against the strong nuclear force. 2. The strong nuclear force is taken as 1 and the electromagnetic force is about 10 to the power minus 2. 3. The weak nuclear force is about 10 to the power minus 13. 4. The gravitational force is about 10 to the power minus 38, far weaker than all the rest. 5. It is noticed at all only because gravity is always attractive and never cancels. _Source: OpenStax College Physics (CC BY 4.0), Ch 4 "Dynamics: Force and Newton's Laws of Motion", section 4.8 Extended Topic: The Four Basic Forces_