? 發問於 科學及數學數學 · 1 十年前

# Maths!!!

1)Tommy spent 60s to complete 400m on a runnimg machine, what was his speed?

(Correct to 3 significant figures.)

2)The weight of Gary is measured to be 65kg with a percentage error of 4%. Find the range of his trye weight.

### 2 個解答

• NCY
Lv 7
1 十年前
最愛解答

1)Tommy spent 60s to complete 400m on a runnimg machine, what was his speed? (Correct to 3 significant figures.)

∵speed = distance/time

∴ his speed

=400/60

= 6.67 ms-1 (Correct to 3 significant figures.)

2)The weight of Gary is measured to be 65kg with a percentage error of 4%. Find the range of his trye weight.

∵maximum percentage error = maximum absoulte error/measured value

∴maximum absoulte error = measured value×maximum percentage error

∴maximum absoulte error

= 65×4%

= 2.6 kg

upper limit

= measured value+maximum absoulte error

= (65+2.6)kg

=67.6kg

lower limit

=measured value﹣maximum absoulte error

=(65﹣2.6)kg

= 62.4kg

∴the range of his trye weight is between 62.4kg to 67.6kg .

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• 1 十年前

1)speed=400/60

=6.67m/s(to 3 sig.fig.)

2)65x4%=2.6

thus, range of it =65-2.6to65+2.6

=62.4to67.6(kg)

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