Open Command Window, type "PowerShell", click enter key. Then past the following line and click enter key:
Get-WmiObject Win32_Process -Filter "name = 'w3wp.exe'" | Select-Object Name, @{"name"="ApplicationPool";expression={(($_).CommandLine).split('"')[1] }},@{"name"="Starttime";expression={$_.ConvertToDateTime($_.CreationDate)}}
Output:
Name ApplicationPool Starttime
---- --------------- ---------
w3wp.exe WebAPITest AppPool 9/21/2020 7:55:43 PM
w3wp.exe apiTestNew AppPool 9/21/2020 7:55:43 PM