Example 7 A steel bar of cross-sectional area 200 mm2 is loaded as shown in Fig. Find the change in length of the bar. Take E as 200 GPa. A B 50 kN+ -20 kN 30 kN 300 mm 500 mm RSITY AQBAL

2-A wheel of diameter d and width w carrying a load F rolls on a flat rail. Estimate the maximum contact pressure for these materials. Por vedit -3D d 5 in 150 mm 3 in W 2 in 40 mm 1.25 in F 600 lbf 2 kN 250 lbf Wheel Material Steel Steel Cast iron Rail Material Steel Cast iron Cast iron.

A rod of different materials is arranged as shown with the corresponding axial forces (see figure 3). Find the maximum value of the force P in kN such that it will not exceed a stress in steel of 140,000 kPa, in aluminum of 90,000 kPa, or in bronze of 100,000 kPa. INPUT THE NUMERICAL VALUE ONLY IN 3 DECIMAL PLACES

3. The bar shown below is composed of two pieces, AC and CD. The bar is attached to the wall at point A. The length L = 10 in. The cross sectional areas are: AAC = 4 in? and AcD = 2 in?. The Young's Moduli are: EAC =20 Msi and Ecd= 15 Msi Two forces are applied at points B and D: PB = 50 kips and PD = 20 kips. Determine: (a) the reaction force at A (specify –→ or +) and (b) the deflection of point D (specify → or +). (Hint for (b): Think about how many pieces you must subdivide the rod into.) Ans: RA = 30 kips (+), dp = 7.9167×10-3 in (E) A В C D Pp L 2L L