A spool of thread has an average radius of 1.00 cm.If the spool contains 47.5 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)15.1
B)756
C)149
D)7.56

Question

Quizplus · Accepted Answer

To find the number of turns of thread on the spool, we can use the formula for the circumference of a circle, $C = 2\pi r$, where $r$ is the radius. Given the average radius is 1.00 cm, the circumference is $C = 2\pi(1) = 2\pi$ cm per turn. To find the total number of turns, we divide the total length of the thread by the length of one turn: $47.5 \, \text{m} = 4750 \, \text{cm}$ (since 1 m = 100 cm), so the number of turns is $4750 \, \text{cm} / 2\pi \, \text{cm} \approx 756$.

A Spool of Thread Has an Average Radius of 1