A spool of thread has an average radius of 1.00 cm.If the spool contains 126 m of thread,how many turns of thread are on the spool? "Average radius" allows us to not need to treat the layering of threads on lower layers.
A) 100
B) 1000
C) 2000
D) 62,800

Question

Quizplus · Accepted Answer

The formula for the length of thread on a spool is:

length = (2πr) * turns

Where r is the radius of the spool and turns is the number of turns of thread on the spool.

To find the number of turns, we rearrange this formula:

turns = length / (2πr)

We are given that the length is 126 m and the average radius is 1.00 cm, which is 0.01 m.

turns = 126 / (2π(0.01)) = 2000

Therefore, the number of turns of thread on the spool is 2000. Answer choice C is correct.

A Spool of Thread Has an Average Radius of 1