After a long study, tree scientists conclude that a eucalyptus tree will grow at the rate of $0\mathrm{.}7\frac{4}{(t1{)}^3}$ feet per year, where $t$ is the time $($in years$).$

$($a$)$ Find the number of feet that the tree will grow in the second year.

$($b$)$ Find the number of feet the tree will grow in the third year.

$($a$)$ The total number of feet grown during the second year is $$ ft$.($Round to three decimal places as needed.$)$