A sewing machine needle moves with a frequency of 2.5 Hz. Approximately how long does it take it to move from the highest point to the lowest point in its travel?
A) 0.40 s
B) 0.10 s
C) 0.20 s
D) 0.80 s
E) 1.25 s

Question

Quizplus · Accepted Answer

The needle moves from the highest point to the lowest point and back, completing one cycle. The frequency of 2.5 Hz means that it completes 2.5 cycles in one second. Therefore, the time taken for one cycle is (1/2.5) seconds, which is equal to 0.4 seconds. However, we only need the time for half a cycle, which is from the highest point to the lowest point or vice versa. So, the answer is 0.4/2 seconds, which is equal to 0.2 seconds. Therefore, the best choice is C.

A Sewing Machine Needle Moves with a Frequency of 2