1. A tensile load is applied to a round steel rod with diameter d=4.2mm. The stress in the rod is =- as described in the F A reading. If this steel can handle a stress of 250 MPa, what is the tensile load F? [kN] Be sure to use the Factor-Label method, solving for the force algebraically before entering any numbers or units. All unit conversions must be done in the main equation. Do not calculate area off to the side - instead, substitute A=- into the main equation. d 4 2. What is the Hall-Petch relationship? How is it useful? 3. 4. Sketch an FCC unit cell. How many atoms belong to the cell? Show calculations. Calculate grain size of a metal alloy (to the nearest 0.1) if there are 72 grains per square inch at 100x.