Question
3. A bar measures 12mmtimes 20mmtimes 1m It has a specific gravity of 2.78. Determine its mass.
Answer
4.2
(285 Votes)
Ingrid
Elite · Tutor for 8 years
Answer
The volume of the bar is 0.24 meters cubed (length 1m X width 0.02m X height 0.012m). The specific gravity of 2.78 g/cm³ is converted to 2780 kg/m³ to match the meter units of volume. Thus, the mass of the bar is 0.24m * 2780kg/m³ = 667.2 kg.
Explanation
This question requires an understanding of volume calculations and the concept of specific gravity to determine the mass of the bar. Basically, first you calculate the volume of the bar using its given dimensions (volume = length × width × height). Afterwards, since the specific gravity of a material is the same as its density except in different units (specific gravity in g/cm³ and density in kg/m³), you convert the specific gravity into appropriate density units (g/cm³ to kg/m³). These sets of conversions are useful because 1 g/cm³ is equal to 1000 kg/m³. The mass of the bar can be computed by multiplying the volume of the bar by its density. This is due to mass essentially being the product of an object’s volume and density.