A hollow hemispherical shell is fixed to the ground by using four ordinary bolts and a steel base plate. A small tube is installed on top of it. To the tube, water is poured up to a height of 800 mm from the bottom of the shell. See figure above.

- Calculate the diameter of the bolts (in mm) that can safely carry an allowable bolt axial stress of 1 MPa.
- Calculate the diameter of the bolts (in mm) that can safely carry an allowable bolt shear stress of 500 kPa.
- Based on your answers in #1 and #2, suggest the best bolt diameter for the setup. Commercial sizes are 12 mm, 16 mm, 20 mm, 25 mm, 28 mm, 32 mm and 36 mm.

Show your solutions.