Joe asked in Science & MathematicsPhysics · 6 years ago

± The Fish Scale (mastering physics)?

A vertical scale on a spring balance reads from 0 to 220N . The scale has a length of 15.0cm from the 0 to 220N reading. A fish hanging from the bottom of the spring oscillates vertically at a frequency of 2.45Hz .

Part A

Ignoring the mass of the spring, what is the mass m of the fish?

2 Answers

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  • Whome
    Lv 7
    6 years ago
    Favorite Answer

    k = 200N / 0.15m = 1333 N/m

    for simple harmonic motion

    f = ω / 2π

    where ω = √(k/m)

    2πf = √(k/m)

    (2πf)² = k/m

    m = k / (2πf)²

    m = 1333 / (2π2.45)²

    m = 5.63 kg

    Edit

    Jully Wum is correct. I erred on the force value. (I really dislike the new Answers format which makes this type of error easier to make)

    m = (220 / 0.15) / (2π2.45)²

    m = 6.19 kg

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  • 6 years ago

    Spring force constant .. k = 220N /0.15m .. .. k = 1466.70 N/m

    Frequency of a loaded spring .. f = 1/T = 1 / {2π√(m/k)}

    f = 2.45 Hz = (1/2π) x √(k/m)

    2.45² = (1/4π²) x k/m

    m = (1/4π²) 1466.7 / 2.45² .. .. ►m = 6.20 kg

    Damon has used an equivalent method .. but the wrong force (200N)

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