Time–decimal conversion: What decimal fraction of one hour is one second? (Choose the closest option to five decimal places.)

Introduction / Context:
Converting between time units and decimal fractions is common in data entry, time sheets, and physics problems. Here, we convert 1 second into the decimal part of one hour and then match to the nearest option provided.

Given Data / Assumptions:

• 1 hour = 60 minutes = 3600 seconds
• Quantity of interest: 1 second as a fraction of 1 hour
• Select the closest value among the options.

Concept / Approach:
The decimal fraction of an hour represented by 1 second is 1/3600. Converting the fraction to a decimal ensures comparability with the choices. Since options are rounded, choose the closest to the true decimal value.

Step-by-Step Solution:

Verification / Alternative check:

Why Other Options Are Wrong:

• .0025 and .0256: Correspond to much larger fractions of an hour (minutes), not seconds.
• .000126: Too small (≈ 1/7937 hours), not equal to one second.

Common Pitfalls:

• Confusing 1/3600 with 1/3660 or 1/360.
• Misplacing the decimal point when converting small fractions.

Final Answer: