$(1$ point$)$ Describe why there is a negative sign in the definition of Poisson's ratio.

$(1$ point$)$ Factor of safety is

$($a$)$ equal to $1$

$($b$)$ less than or equal to $1$

$($c$)$ greater than or equal to $1$

$(4$ points$)$ For each statement, write if it is true or false.

$($a$)$ True or False: Ductile materials rupture in compression.

$($b$)$ True or False: Brittle materials fail at a larger strains compared to ductile materials.

$($c$)$ True or False: Ductile materials are characterized by yielding.

$($d$)$ True or False: Brittle materials are characterized by sudden failure.

$(1$ point$)$ Material first begins to deform plastically upon reaching

$($a$)$ elastic limit

$($b$)$ yield stress

$($c$)$ ultimate stress