1. The problem statement, all variables and given/known data A string prq which is fixed at p and where q is vertically below p. r is a smooth ring threaded on the string which is made to rotate at an angular velocity ω rad/s in a horizontal circle centre q, the string being taut. If |pq| = 0.12 m, |pr| + |rq| = 0.18 m, show that ω = 294^(1/2) rad/s. 2. Relevant equations m(ω^2)r 3. The attempt at a solution I was able to solve this and get the correct answer, by setting the sum of the horizontal tension equal to the cent. force, but I had to assume that the tension in the qr part of the string is the same as the tension in the pr part. What I don't understand is how we know that the tension in both parts of the string are the same considering they are at different angles. I was thinking that because the string is massless, it must be the same everywhere. But then I encountered another question: For this question a ball is connected by one string (it's massless) and I had to find the tension in the lower and upper part of the string. I was able to solve this, but what's confusing me is when to know when the tension is the same everywhere in the string, and when it's different.