An $8\mathrm{.}0-$g acorn falls from a tree and lands on the ground $10\mathrm{.}0$ m below with a speed of $11\mathrm{.}0\frac{m}{s}.$

$($a$)$ What would the speed of the acorn have been if there had been no air resistance?

$($b$)$ Did air resistance do positive, negative or zero work on the acorn? Why?

$($c$)$ How much work was done by air resistance?

$($d$)$ What was the average force of air resistance?