i have a disabled iPad and no iTunes. It shows an iTunes screen when plugged into a power source but no response when plugged into computer

Presumably your iPad indicates that it must be restored:

If you see the Restore screen on your iPhone, iPad, or iPod touch - Apple Support

These support pages outline the available methods to restore an iPad - either from a backup, or to Factory Settings:

Restore your iPhone, iPad or iPod touch from a backup – Apple Support

Restore your iPhone, iPad or iPod to factory settings – Apple Support

Restore all content to iPad from a backup - Apple Support

You’ll need access to either a Windows PC (with iTunes for Windows installed - or more recent Apple Devices App) or a Mac computer (with iTunes or Finder - as appropriate for the installed version of macOS).

Download and use iTunes for Windows – Apple Support

Update to the latest version of iTunes – Apple Support

Apple Devices App (Windows PC):

https://apps.microsoft.com/detail/9np83lwlpz9k?hl=en-ms&gl=MS

If your iPad isn’t recognised when connected to a computer with appropriate software installed, try using a different USB port. If the computer has both USB-C and USB Type-A ports, try using the latter. Otherwise, this support page should help with troubleshooting connection difficulties:

If your computer doesn't recognize your iPhone or iPad - Apple Support

Use of a PC or Mac computer is unavoidable. If you don’t have access to a suitable computer of your own, that of a helpful friend or family member will suffice. Alternatively, the technicians at the Genius Bar of your local Apple Store or Apple Authorised Service Provider (AASP) will be delighted to assist.

Genius Bar Reservation and Apple Support Options - Apple

1. which model of iPad is it? (you can check it on the lower half on the back side along with the serial number)
2. Are there any Physical damages to it?

First try connecting another device to the iMac to check if it's the problem of the iMac/iTunes or the iPad. if you cannot access the internal storage/ music/pictures of the other device in the iTunes application in your iMac then it might be the problem and you can try updating iTunes. Using the same cable (if possible) connect the iPad & then open iTunes, if it still shows the same signs then we might use a different approach if possible. You can also try using different USB port & Different cables also.

you can also enter the serial number of your iPad here "Check your device’s coverage (apple.com)" to get more info about the device & also if its still under Warranty you can take it to an Apple Store.

hope this helps you ;)