Although the orbit in Figure 3 may seem to rotate uniformly, i.e., at a constant angular speed, this is true only for circular orbits. If the orbit rotates at an angular speed Ω, the angular speed of the second particle is faster or slower than that of the first particle by Ω ; in other words, the angular speeds would satisfy the equation ω 2 = ω 1 + Ω. However, Newton's theorem of revolving orbits states that the angular speeds are related by multiplication: ω 2 = kω 1, where k is a constant. Combining these two equations shows that the angular speed of the precession equals Ω = (k − 1) ω 1. Hence, Ω is constant only if ω 1 is constant. According to the conservation of angular momentum, ω 1 changes with the radius r