Define the Young modulus for a material in terms of stress per unit strain.
A metal wire P that obeys Hooke’s law is stretched within its limit of proportionality. On Fig. 4.1, sketch how the tensile force $F$ in the wire changes with extension $x$.
State the name of the quantity shown by the gradient of the line in Fig. 4.1.
State the name of the quantity shown by the area under the line in Fig. 4.1.
Another wire Q is made from a metal with twice the Young modulus of the metal used for wire P in (b). Wire Q has the same volume as wire P but double the cross-sectional area of wire P. The two wires are extended by equal tensile forces while still within their limits of proportionality. State and explain how the extension of wire Q compares with the extension of wire P.