2.1 Calculate the diameter of a shaft that is loaded as shown in figure 2.1 below if the first critical speed is limited to 10 000 rpm. All the lengths on the shaft are equal and are 250 mm long. (15)

Assume W1 = 220 N, W2 =130 N and Young's Modulus E = 207 GPa.

The shaft should be assumed to be massless and the bearings at RL ad RR are rigid.

W 1 RL X X W2 L2 RR L3