A gas is confined in a 0.3m diameter cylinder by a piston, on which rests a weight. The mass of the piston is 85 kg. The local acceleration of gravity is 9.807 m/s, and atmospheric pressure is 101.33 kPa. If the absolute pressure of the gas is 1.4 bar, calculate the mass in kilograms of the weight.

Respuesta :

Explanation:

Force applied on the gas will be as follows.

                   [tex]F_{gas} = F_{atm} + (m + M) g[/tex]

As,   F = pressure × area. Hence, calculate the forces as follows.

                  [tex]F_{gas}[/tex] = pressure × area

                         = [tex]1.4 \times 10^{5} Pa \times \pi \times (\frac{0.3}{2})^{2}[/tex]

                          = [tex]1.979 \times 10^{4}[/tex] N

                  [tex]F_{atm}[/tex] = pressure × area

                            = [tex]1.0133 \times 10^{5} \times \pi \times (\frac{0.3}{2})^{2}[/tex]

                            = [tex]1.432 \times 10^{4}[/tex] N

      [tex]F_{gas}[/tex] - [tex]F_{atm}[/tex] = [tex]5.47 \times 10^{3}[/tex] N

Substituting the calculated values into the above formula as follows.

                [tex]F_{gas} = F_{atm} + (m + M) g[/tex]

              [tex]F_{gas} - F_{atm}[/tex] = (m + M) g

              [tex]5.47 \times 10^{3}[/tex] N = [tex](m + 85) \times 9.8[/tex]    

              [tex]5.47 \times 10^{3}[/tex] N = [tex]9.8m + 833[/tex]

                               m = 472.76 kg

Thus, we can conclude that the mass is 472.76 kg.