The mass of a cube, M (kg), is proportional to the cube of the length of its edge, L(m). The mass of the cube is 80 kg when the length of its edge is 35 cm. Work out M (to 2 DP) when L=0.3 m

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  50.38 kg

Step-by-step explanation:

The mass is proportional to the cube of edge length, So, if the edge length is decreased by a factor of 30/35 = 6/7, the mass is decreased by a factor of (6/7)³. That is, the smaller cube will have a mass of ...

  (80 kg)(6/7)³ ≈ 50.38 kg

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If you want to write an equation, you can write the equation for the proportionality:

  M = kL³

  80 kg = k(0.35 m)³

  k = 80/0.35³ kg/m³

Then for the shorter length, we have ...

  M = k(0.3 m)³ = 80(0.3/0.35)³ kg = 80(6/7)³ kg ≈ 50.38 kg . . . . as above

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step-by-step explanation:

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step-by-step explanation:

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