PS> $serviceName = Get-WmiObject Win32_service -filter "displayname = 'Security Center'" |select -expandproperty name
PS> sc.exe start $serviceName

PS> Get-WmiObject Win32_service -filter "displayname = 'Security Center'" |select -expandproperty name |sc.exe start "$_"
DESCRIPTION:
        Starts a service running.
USAGE:
        sc <server> start [service name] <arg1> <arg2> ...

Get-WmiObject Win32_service -filter "displayname = 'Security Center'" |select -expandproperty name |ForEach-Object {
  sc.exe start "$_"
}