Final answer:
To calculate the stress in the bronze bar, we divide the force acting on it by its area. The force is half the weight of the bar, and the area is given. By substituting values into the formula, we find that the stress in the bronze bar is 159.30 N/mm².
Step-by-step explanation:
To calculate the stress in the bronze bar, we need to find the force acting on it and divide it by the area of the bar. Since the bar is supported at either end by a cable, we can assume that the tension in each cable is the same and equal to half the weight of the bar. The weight of the bar can be calculated using the formula weight = mass × gravity, where mass is given as 1300 kg and gravity is approximately 9.8 m/s². Therefore, weight = 1300 × 9.8 = 12,740 N.
The tension in each cable is then 12,740 N ÷ 2 = 6,370 N. The stress can be calculated using the formula stress = force ÷ area. For the bronze bar, the area is given as 40.05 mm². Converting to meters, we get 40.05 × 10⁻⁶ m².
Now we can calculate the stress: stress = 6,370 N ÷ (40.05 × 10^-6 m²) = 159.30 × 10^6 N/m². However, the question asks for the stress in N/mm², so we need to convert the units: 159.30 × 10^6 N/m² = 159.30 N/mm².