? asked in 科學及數學數學 · 1 decade ago

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 Answers

Rating
  • NCY
    Lv 7
    1 decade ago
    Best Answer

    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 .

  • 1 decade ago

    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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