1.) The standard kilogram is a platinum-iridium cylinder 39.0mm in height and 39
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Question
1.) The standard kilogram is a platinum-iridium cylinder 39.0mm in height and 39.0mm in diameter. What is the density of the material?
2.) A major motor company displays a die-cast model of its first automobile, made from 9.35 kg of iron. to celebrate its one-hundredth year in business, a worker will recast the model in gold from the original dies. What mass of gold is needed to make the new model?
3.) A proton, which is the nucleus of a hydrogen atom, can be modeled as a sphere with a diameter of 2.4fm and a mass of 1.67x10-27kg. Determine the density of the proton and state howit compares with the density of lead.
Explanation / Answer
the standard kilogram is a platinum-iridium cylinder 39.0 mm in height and 39.0 mm in diameter. First you must convert. 1 millimeter = 0.001 meters h=39mm=0.039m Diameter=0.039m Raduis=0.0195m Now you can calculate the volume V=ha=h*pr^2 h is height a is area r is raduis V=0.039*(22/7)*(0.0195)^2=0.0000466m^3 ?(density)= m / v ?=1 / 0.0000466=21459.23 kg / m^3=21.459 g / cm^3 2. i guess this is a question re: relative density. look up the density of iron in g/cm^3. call this d_iron. as density = mass/volume, then volume = mass/density. so the volume of iron V_iron = 9350 g / d_iron. the units will be cm^3. to replace the same volume with gold, the mass of gold needed is mass_gold = V_iron * d_gold, where d_gold is the density of gold. look that up this will boil down to the ratio of densities, as the volumes are the same in the two cases by definition 3..
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