3. Fig. 1 shows a gas contained in a vertical piston- cylinder assembly. A vertical shaft whose cross- sectional area is 0.8 cm is attached to the top of the piston. Determine the magnitude, F, of the force acting on the shaft, in N, required to maintain a gas pressure of 3 bar. The masses of the piston and attached shaft are 24.5 kg and 0.5 kg, respectively. The piston diameter is 10 cm. The top of the piston (except the part attached to the shaft) is exposed to the atmospheric pressure, which is 1 bar. The piston moves smoothly in the cylinder and the gravitational constant g-9.81 m/s Piston- F - A = 0.8 cm Shaft- Palm = 1 bar Gas at p = 3 bar Fig. 1 D= 10 cm