Final answer:
To find the diameter of the rod, calculate the stress and strain caused by the truck passing by and solve for the diameter using the equation diameter = 2 x strain x original length / pi.
Step-by-step explanation:
In order to find the diameter of the rod, we need to calculate the stress and strain caused by the truck passing by. The stress is the force per unit area and is given by dividing the weight of the truck by the cross-sectional area of the rod. The strain is the change in length divided by the original length. By rearranging the equation for strain, we can solve for the diameter of the rod.
Stress = Weight / Area
Strain = Change in Length / Original Length
Solving for the diameter:
Diameter = 2 x Strain x Original Length / pi