GATE Mechanical Engineering (ME) 2014 Shift 2 Solved Paper

A spherical balloon with a diameter of 10 m, shown in the figure below is used for advertisements. The balloon is filled with helium (R_He = 2.08 kJ/kg K) at ambient conditions of 15°C and 100 kPa. Assuming no disturbances due to wind, the maximum allowable weight (in newton) of balloon material and rope required to avoid the fall of the balloon (R_air = 0.289 kJ/kg K) is ______