$2-6.$ The wire $AB$ is unstretched when $=45.$ If a load is applied to the bar $AC,$ which causes $$ to become $47,$ determine the normal strain in the wire.

$2-7.$ If a horizontal load applied to the bar $AC$ causes point $A$ to be displaced to the right by an amount $L,$ determine the normal strain in the wire $AB.$ Originally, $=45.$

Probs. $2-6/7$