Question $4$

$(14$ marks$)$

In an experiment to determine the modulus of elasticity of a sample of mild steel, a wire is loaded and the

corresponding extension noted. The results of the experiment are:

$($a$)$ Plot the load$/$extension graph.

$($b$)$ If the mean diameter of the wire is $1\mathrm{.}3$ mm and its length is $8\mathrm{.}0$ m $,$ determine the modulus of

elasticity of the sample.

$($c$)$ From your graph identify the limit of proportionality and determine the stress at this point. $($Read

this value off your graph$)$

$($d$)$ If a tie bar $2\mathrm{.}5$ m long and $40$ mm diameter is to be made from this material, what will be the

maximum load it can carry if a factor of safety of $3$ is required?