You have seen that a shorter period means a greater frequency. A turntable has a period of 0.5 s.
Exactly how many revolutions does it fit into each second?
Each revolution takes 0.5 s, so the revolutions that fit into one second number 1 ÷ 0.5 = 2.
The turntable's frequency is f = 2 Hz.
One equation says that count for every spinning object.
In symbols: f = 1/T.
With T in seconds, f comes out in hertz.
Frequency and period are reciprocals of each other: each equals 1 divided by the other.
The equation retells the earlier comparison precisely: a shorter period divides 1 into a bigger frequency.
A cooling fan has a period of 0.1 s. Enter its frequency in Hz.
Dagny says: 'An exercise-bike wheel with a period of 0.4 s has a frequency of 2.5 Hz.' Is Dagny correct?
A bicycle wheel has a period of 0.2 s. Calculate its frequency.
Write down the values:
T = 0.2 s, f = ?
Write down the equation:
f = 1/T
Substitute in the values, and calculate:
f = 1 / 0.2 = 5
The wheel's frequency is 5 Hz.
A wind turbine has a period of 4.0 s. Calculate its frequency.
Write down the values:
T = 4.0 s, f = ?
Write down the equation:
f = 1/T
Substitute in the values, and calculate:
f = 1 / 4.0 = 0.25
The turbine's frequency is 0.25 Hz: a quarter of a revolution each second.
A wheel's period doubles. What happens to its frequency?
An airport luggage carousel completes one revolution every 40 s. Enter its frequency in Hz.
Astrid knows a wheel's period in seconds. How does she calculate its frequency in Hz?
Which statement about a spinning object is correct?