(i)find lifting force of a 4 kg cork lifebelt in sea water if densities of cork and sea water are 0.2 *10^3 kg/m^3 and 1.03*10^3 kg/m^3
(ii)a crown made of gold and copper weighs 210 g in air and 198 g in water.The weight of gold in crown is (density of gold 19.3 g/cm^3 and density of copper is 8.5 g/cm^3
(iii)what will be heigth of liquid of density 3.4 g/cm^3 in barometer at a place where it is 70 cm of mercury barometer

1
specify the value of g = 10m/sec/sec or 9.8 ..
ok. i do that now.

Answers

2014-12-19T20:47:40+05:30

This Is a Certified Answer

×
Certified answers contain reliable, trustworthy information vouched for by a hand-picked team of experts. Brainly has millions of high quality answers, all of them carefully moderated by our most trusted community members, but certified answers are the finest of the finest.
1)  
         Volume of cork life belt = 4 kg / (200 kg/m³) = 0.02 m³
    if the entire volume of cork life belt is immersed in water, it will displace 0.02 m³ of sea water.  Then, the force of buoyancy will be

            0.02 m³ * 1030 kg/m³ * 9.81 m/sec²  = 202.086  Newtons

      Additional load it can carry (excluding its own weight )
                              =  202.086 N - 4 * 9.81 = 162.846 Newtons

2)
          wt in air = 210 gms = density  * volume
         wt in water = 198 gms => buoyancy force = 210-198 = 12 gms equivalent
            12 * g = Volume of crown * 1 gm/cm³ * g
             volume of crown = 12 cm³

    Let volume of Gold in Crown be x cm³.    volume of copper (12 - x) cm³
         weight of crown =  x * 19.3 + (12 - x) 8.5 =  210
                     x = 10 cm³   
       =>   weight of gold in crown = 19.3 * 10 = 193 gms

3)  

     Pressure is proportional to the height of the liquid column and density.
                 P = K * density * g * height
     As the pressure is same = atmospheric pressure, height is inversely proportional to the density.

                  height / 70  = 13.6 / 3.4
             =>               height = 280 cm

1 5 1