Question

A string trimmer is a tool for cutting grass and weeds; it utilizes a length of nylon "string" that rotates about an axis perpendicular to one end of the string. The string rotates at an angular speed of 38 rev/s, and its tip has a tangential speed of 51 m/s. What is the length of the rotating string

Answer 1

0.214 m.

Explanation:

Given:

w = 38 rev/s

To rad/s,

38 rev/s × 2pi rad/ 1 rev

= 238.76 rad/s

V = w × r

51 = 238.76 × r

r = 0.214 m

Note, radius of the motion is the length of the string.