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Digiron [165]
3 years ago
11

An object weigh 40N in air ,weigh 20N when submerged in water,and 30N when submerged in a liquid of unknown liquid density.what

is the density of unknown of liquid?
Physics
1 answer:
muminat3 years ago
7 0

Answer:

The density is  \rho_u  =500 kg /m^3

Explanation:

From the question we are told that

    The weight in air is  W_a =  40 \ N

     The weight in water is  W_w =  20 \ N

     The weight in a unknown liquid is  W_u  =  30  \ N

Now according to Archimedes principle the weight of the object in water is mathematically represented as

       W_w =  W_a -m _w g

Where  m_w is he mass of the water displaced

 substituting value

       m_w g  =  40 -20

      m_w g  = 20 \ N --- (1)

Now according to Archimedes principle the weight of the object in unknown  is mathematically represented as

       W_u =  W_a -m _u g

Where  m_u is he mass of the unknown liquid  displaced

 substituting value

       m_u g  =  40 -30

      m_u g  = 10 \ N ---(2)

dividing equation 2 by equation 1

      \frac{m_ug}{m_wg}  =  \frac{10}{20}

     \frac{m_u}{m_w}  =  \frac{1}{2}

=>  m_u =  0.5 m_w

Now since the volume of water and liquid displaced are the same then

      \rho _u =  0.5 \rho_w

This because

         density =  \frac{mass}{volume}

So if  volume is constant

         mass = constant * density

Where \rho_u is the density of the liquid

     and  \rho_ w is the density of water which is a constant with a value \rho_w = 1000 kg/m^3

So

        \rho_u  = 1000*0.5

        \rho_u  =500 kg /m^3

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kenny6666 [7]

Answer:

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            B = 1.25 10⁻⁶ T

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