Astrid knows a wheel's period in seconds. How does she calculate its frequency in Hz?
Dilys times the swells at a ladder on a sea wall with a stopwatch: one complete wave slides past every half second, steady as a clock.
Timing one wave and counting waves per second are two reads of the same rhythm. This lesson re-enters both and ties them together.
Earlier in the course, you met the period: the time for one complete revolution, written T, measured in seconds.
A wave has a period the same way. The time for one complete wave to pass a fixed point is the wave's period T.
Dilys's swells take 0.5 s per wave: T = 0.5 s. And if each wave takes half a second, two complete waves pass each second: f = 2 Hz.
A 2 Hz wave has a period of 0.5 s, because 1 ÷ 2 = 0.5.
To find a period from a frequency, divide 1 by the frequency.
A greater frequency means more waves each second, so each one takes less time: a shorter period.
A wave machine makes waves at 8 Hz. Find the period of the waves.
f = 1/T, so the period comes from dividing 1 by the frequency.
1 ÷ 8 = 0.125
T = 0.125 s: each complete wave takes 0.125 s to pass.
A buoy camera shows ripples arriving at 25 Hz. Find their period.
Divide 1 by the frequency.
1 ÷ 25 = 0.04
T = 0.04 s per complete wave.
Ripples arrive at a pool ladder at 4 Hz. Enter the ripples' period in s.
A wave tank's paddle makes waves at 20 Hz. Enter the waves' period in s.
Beata says: 'Of two wave trains, the one with the greater frequency has the shorter period.' Is Beata correct?
During a test run of a wave generator, a harbor-model sensor logs ripples arriving at 50 Hz. Enter the period of the ripples in s.
A wave's period is 0.3 s. Which statement is correct?
A metronome drives a wave tank's paddle so that waves leave it at 5 Hz. Enter the period of the waves in s.