"ELASTIC LIMIT, TENSION and YOUNG'S MODULUS. Below the elastic limit, or maximum stress that can be applied to an object without causing permanent deformation, a tension or compressive force FORCE actson an object of length initial LENGTH0 and cross-sectional area AREACROS to change its length DELTALEN. Young's modulus YOUNGMOD is the ratio: (longitudinal stress)/(longitudinal strain) and it has the dimensions of a stress (N/m^2 or Pascal Pa and pound/in^2). *** Answer to problem *** (c) Copyright PCSCC, Inc., 1993 Note: the polyimide rod is assumed to have a circular cross section. Its area is thus pi*(diameter/2)^2. Steps to follow are: 1) Calculate cross sectional area of ployimide rod. Enter diameter in meters. 2) Determine maximum force that produces the elastic limit stress and 3) Solve Young's modulus equation for change of length DELTALEN. Set DIAMETER=4*10^-3 or 4e-3 which is .004 m. Set ELASTLIM=5e8. Set LENGTH0=6.Finally, set Young's modulus YOUNGSMO=4e11. The change in length is DELTALEN= .0075 m or 7.5mm. ||A steel-like polyimide rod is 6 m long and 4 mm in diameter. The elastic limit is a stress of 5.0x10^8 Pa and Young's modulus is 4x10^11 Pa. (a) How much can the rod be stretched before exceeding its elastic limit? Type comma key to see answers. Type (F2) to return to helpfile."
