Recent content by BP Leonard

We often see warnings such as: "such-and-such a formula is true only if theta is 'measured in radians'." For example: "s = r theta" or "d[sin(theta)]/d(theta) = cos(theta)." Unfortunately, the warning is not correctly (or completely) stated. What is meant is: "theta is the (dimensionless)...

The "controversy" about whether angles should be treated as dimensional quantities (with an independent dimension called angle, with, for example, symbol A) or as dimensionless numbers has been going on for a long time. In fact, there should be no controversy. When I turn my head from looking...

To Mark44: Angles are dimensional physical quantities and have been recognised as such, either implicitly or explicitly, for millennia. Actually, in the International System of Quantities (ISQ), "angles" themselves are considered to be dimensionless and are "defined" as the ratio of the...

If we have a circle with radius r and a sector of the circle with central angle theta, the generally accepted formula for finding the corresponding arc-length of the sector is; s = r theta usually with the stipulation that "theta must be in radians." So let's say that r = 0.1 m and theta = 30...