Answer:
- A: 6.624×10⁸ m/day
- B: 1.9872×10¹⁰ m
- C: 19.872 Gm or 1.9872×10¹ Gm
Step-by-step explanation:
For the first two parts, you need to know the number of hours in a day, and the number of days in 30 days (!?). No doubt, these numbers are familiar to you.
Part A.
The distance traveled in 24 hours (1 day) is 24 times the distance traveled in one hour.
distance per day = (27,600,000 m/h)×(24 h/day) = 662,400,000 m/day
Since you are familiar with place value and powers of 10, you know you can write this as ...
662,400,000 m/day = 6.624×100,000,000 m/day = 6.624×10⁸ m/day
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Part B.
Using the result from Part A, we know that 30 days' travel will be 30 times one day's travel:
distance in 30 days = (30 days)×6.624×10⁸ m/day = 198.72×10⁸ m
= 1.9872×10¹⁰ m
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Part C.
Your judgment is required to determine a "suitable unit." I might choose gigameters, abbreviated Gm. "giga-" is a prefix meaning 10⁹, so the distance traveled in 30 days could be written as ...
1.9872×10¹⁰ m = 19.872×10⁹ m = 19.872 Gm = 1.9872×10¹ Gm
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Comment on "suitable unit"
In my engineering career, I would often choose units from the list of SI prefixes, so that exponents were a multiple of 3. That means any given measurement or calculation result ranged from 1 to 999, multiplied by some suitable choice of units. Here, the distance traveled in 30 days would be left as (about) 19.9 Gm. The choice of units is intended to avoid the need for scientific notation.
The meaning of "a more suitable unit in scientific notation" is unclear in this context. I would say a "more suitable unit" is Gm, whose value in scientific notation is 10^9 m or 10^6 km.
