Question

The string rotates at an angular speed of 47 rev/, and its tip has a tangential speed of 54 m/. What is the length of the rotating string?

Answer 1

The rotating string is shown in Fig. The angular frequency of the string’* rotation is

We have the speed of the tip of the string (which is a distance r from the axis), so from we can get the length of the string, r:

The string is 18.3 cm long.