Question

Density is a physical property which plays a very important role in our daily life. It is very widely used in all field of engineering. Density is widely used for choosing the suitability of a material for a specific purpose.

a) Discuss how density is finding its application in Marine engineering field in not more than 100 to 150 words.
b) Describe the way in which you can determine the density of given substances. Also explain the tools which are used for finding the density. Explain in detail.
c) You are given a cylindrical shaped silver having diameter X cm and height Y cm.
[ You can take X – the first two digits of your student ID and Y – the last two digits of your student ID. For e.g., If the student’s ID is 1875-18, The X = 18 and Y = 75]. The density of silver is 10.5 g/cm3. Calculate the mass of the silver shape given to you in kg/m3.
[ for conversion you can use - 1 m = 100 cm and 1 kg = 1000 g]

This all information

Answer 1

ANSWER

a)

Density is a physical property of any matter, which is usually defined as the ratio of mass to volume. When it come to marine engineering, the specific density of the material has to be considered. Specific density is the ratio of the density of the material to the density of water. It is important to know the specific density, so that the floating properties of the material can easily be understand. If the specific density is less than 1, then that material floats over water for sure. But if its specific density is greater than 1, then it will sink. In marine engineering, specially in ship designig , the material used for making ships are steel and their density is more than the density of water. Ships can float because they have special air tanks to proide larhe volumes, thereby decreasing the density. Together with the buoyant force that the water exerts on the ship, this reduced density enables the ship to float.  Another importance of the application of density is, fluid flow through a pipe. this we can easily understand by Bernoullis principle of energy coservation in fluid flow. We can understand that the density of fluid affects the fluids velocity, pressure and even height.

b)

Density can be measured using the formula density = Mass / Volume

The tools needed are, a balance to measure the mass , length measuring apparatus like a meter scale, a vernier calliper or a screw gauge .

For example a cubical or cuboidal shape object a length measuring apparatus is needed. But for a cylindrical or spherical objects , their radius is important which can be measured with the help of a vernier or a screw gauge

c)Given

Diameter = X cm

Height = Y cm

Density of silver = 10.5 g/cm3 = 10.5 x 10-3 /( 10-2 )2

= 10.5 x 103 Kg / m3

Volume of the given silver shape = D2 h/4 = 3.14 x X2 x Y/4

AS per the given example Volume = 3.14 x (0.18)2 x (0.75)/4 = 0. 0763m3

Mass of the object = Density x Volume = 10.5 x 103  x  0. 0763 = 0.80115 kg