Question

A company produces plastic discs for use in other products. the company produces 2x10^7 discs daily, each 1.55mm thick.

A.if the discs from one day's production were stacked one on top of the other, how tall would the stack be?
B.use the results from part A and the facts that 1km=100m and 1m=1000mm to find the height of the stack in meters and kilometers.
C.which unit is most appropriate to use for the height of the stack? Explain

Answer 1

9514 1404 393

Answer:

A: 3.1×10^7 mm

B: 3.1×10^4 m; or 31 km

C: km

Explanation:

The height of the stack would be ...

(2×10^7)(1.55 mm) = 3.1×10^7 mm

= 3.1×10^7×(10^-3 m) = 3.1×10^4 m

= 3.1×10^4×(10^-3 km) = 3.1×10^1 km = 31 km

A. The height of the stack would be 3.1×10^7 mm

B. The height of the stack would be 3.1×10^4 m, or 31 km

C. Kilometers are appropriate for the overall height of the stack.

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Additional comment

SI units are conveniently named in powers of 10 that are 3 apart. This makes it possible to choose units that give measurements in the range of 1 to 1000 units.