Respuesta :

Answer:

The  density is  [tex]\rho_{block} =  356 \ kg/m^3 [/tex]

Explanation:

From the question we are told that

   The proportion of the plastic under water is  p =  0.356

Generally at equilibrium the buoyant force is equal to the weight of the block i.e

         [tex]B =  mg[/tex]

Generally the Buoyant force is mathematically represented as

          [tex]B  =  \rho  *  V *  g[/tex]

Here [tex]\rho[/tex] density of the water with value

[tex]\rho =  1000 kg/m^3[/tex] ,

V is the volume of water displaced by the block which is [tex] p * V_{block [/tex] ,  

So

    [tex]1000 *  0.356 V_{block}  *  g  =  m *  g[/tex]

Here m is the mass of the block which is mathematically represented  as

        [tex]m  =  \rho_{block}  *  V_{block}[/tex]

So

         [tex]1000 *  0.356 V_{block}  *  g  =   \rho_{block}  *  V_{block}*  g[/tex]

         [tex]1000 *  0.356 V_{block}  =   \rho_{block}  *  V_{block}*  g[/tex]

       =>    [tex]\rho_{block} =  1000 *  0.356[/tex]

      =>    [tex]\rho_{block} =  356 \ kg/m^3 [/tex]