Mechanical Properties Of Solids

Stress = =
Given: N, diameter = 2 mm = m ⇒ radius = m
Area m
So, Stress = Pa

Step 1: Identify the given information and the quantity to be calculated.
Given: \begin{itemize} \item Radius of the steel rod ( ) = 10 mm. \item Length of the steel rod ( ) = 80 cm (This is additional information not required to calculate stress). \item Force applied ( ) = 66 kN. \end{itemize} We need to calculate the longitudinal stress ( ) on the rod. Step 2: Convert the given values to SI units.
Radius: Force: Step 3: Recall the formula for longitudinal stress.
Longitudinal stress ( ) is defined as the force ( ) applied per unit cross-sectional area ( ) of the object: Step 4: Calculate the cross-sectional area of the rod.
Since the rod is circular, its cross-sectional area ( ) is given by the formula for the area of a circle: Using the approximation : Step 5: Calculate the longitudinal stress.
Now, substitute the values of and into the stress formula: To express this in the form of the options, we adjust the decimal: Step 6: Compare the calculated stress with the given options.
The calculated stress is approximately , which matches option (4). The final answer is .