Answer :

To determine the frequency of a pendulum, we need to understand the relationship between the number of swings and the time taken. Frequency is defined as the number of cycles (or swings, in this case) per unit of time and usually measured in Hertz (Hz), where 1 Hz equals one cycle per second.

Let's solve this step-by-step.

1. Given Data:
- Number of swings (cycles) = 40
- Time taken (seconds) = 20.0

2. Formula for Frequency:
[tex]\[ \text{Frequency} = \frac{\text{Number of cycles}}{\text{Time in seconds}} \][/tex]

3. Substitute the Given Values:
[tex]\[ \text{Frequency} = \frac{40 \text{ cycles}}{20.0 \text{ seconds}} \][/tex]

4. Calculate the Frequency:
[tex]\[ \text{Frequency} = 2.0 \text{ Hz} \][/tex]

Therefore, the frequency of the pendulum is [tex]\(2.0 \text{ Hz}\)[/tex].

Answer: B. 2.0 Hz