Two horizontal forces act on a $1\mathrm{.}7$ kg chopping block that can slide over a frictionless kitchen counter, which lies in an xy plane. One force is F$=(3\mathrm{.}4$N$)1+(6\mathrm{.}4$ N$)7.$ Find the acceleration of the chopping block in unit$-$vector notation when the other force is $($a$)$ F$2=(-3\mathrm{.}4$N$)+(-6\mathrm{.}4$N$)$ J$.($b$)$ F$2=(-3\mathrm{.}4$N$)1+(6\mathrm{.}4$N$)$ J$.$ and $($c$)$ F$2(3\mathrm{.}4$N$)+(-64)$