The International Space Station orbits Earth at an average speed of 4.76 miles per second. What is the space station's...

1. TRANSLATE the problem information

• Given information:
  • Speed = \(\mathrm{4.76\ miles\ per\ second}\)
  • Need to convert to: \(\mathrm{miles\ per\ hour}\)

2. INFER the conversion strategy

• To convert from "per second" to "per hour", I need to find how many seconds are in 1 hour
• Strategy: Use time unit relationships to build a conversion factor, then multiply

3. INFER the time relationships needed

• \(\mathrm{1\ minute = 60\ seconds}\)
• \(\mathrm{1\ hour = 60\ minutes}\)
• Therefore: \(\mathrm{1\ hour = 60 \times 60 = 3{,}600\ seconds}\)

4. SIMPLIFY by applying the conversion

• Set up: \(\mathrm{4.76\ miles/second \times 3{,}600\ seconds/hour}\)
• The "seconds" units cancel out, leaving miles/hour
• Calculate: \(\mathrm{4.76 \times 3{,}600 = 17{,}136}\) (use calculator)

Answer: D. 17,136.0

Why Students Usually Falter on This Problem

Most Common Error Path:

Weak INFER skill: Students correctly find that \(\mathrm{1\ minute = 60\ seconds}\), so they multiply \(\mathrm{4.76 \times 60 = 285.6}\) and think they're done. They stop at "miles per minute" instead of recognizing they need to convert minutes to hours for the final answer.

This leads them to select Choice A (285.6).

Second Most Common Error:

Inadequate SIMPLIFY execution: Students recognize the need to go from seconds to hours but make calculation errors. They might incorrectly calculate the conversion factor (thinking \(\mathrm{1\ hour = 120\ seconds}\) instead of \(\mathrm{3{,}600}\)) or make arithmetic mistakes in the final multiplication.

This causes confusion and may lead to selecting one of the other incorrect choices or guessing.

The Bottom Line:

This problem requires students to think through a two-step time conversion (seconds → minutes → hours) rather than stopping after the first step. The key insight is recognizing that "per hour" requires converting through both minute and hour relationships, not just one of them.