kill is not working within awk

[jyoti100in]

Hallo...
I need to run this script to protect the user1 from more than 30% cpu usage.But kill is not working within awk.What should I do ??

#!/bin/bash

ps -fuU user1 >> psFile

awk '{ if( $3 > "30")
kill -9 $2 }' psFile
rm psFile

Help me.Thank u.