If you cannot open the Yelp app on your iPad, follow these step-by-step troubleshooting measures to resolve the issue:

1. Force Close the App:
- Swipe up from the bottom of the screen (or double-click the Home button if your iPad has one).
- Find the Yelp app and swipe it off the screen to close it.

2. Restart Your iPad:
- Press and hold the power button until you see the "slide to power off" option.
- Slide it to turn off your device.
- Once it's completely off, press and hold the power button again until the Apple logo appears.

3. Check for App Updates:
- Open the App Store on your iPad.
- Tap on your profile icon at the top right corner.
- Scroll down to see pending updates. If there's an update available for Yelp, tap "Update."

4. Clear Cache (if applicable):
- While iPads don’t have an explicit cache clear option for apps, you can uninstall and reinstall the app as a way to reset it.

5. Uninstall and Reinstall the Yelp App:
- Tap and hold the Yelp app until it starts to jiggle.
- Tap the "X" or "Remove App," then confirm you want to delete it.
- Go to the App Store, search for Yelp, and download it again.

6. Check for iOS Updates:
- Open the Settings app.
- Go to "General" and then tap "Software Update."
- If an update is available, download and install it.

7. Reset Network Settings:
- Open the Settings app and go to "General."
- Tap "Reset" and then select "Reset Network Settings."
- This clears saved WiFi networks and passwords, so you will need to reconnect to those.

8. Report Issues:
- If you’ve tried all these steps and the app still won’t open, consider submitting a bug report through Yelp’s Customer Support here - [learn more].

For further assistance and discussions, you might find community threads valuable, such as ones on Apple Support Community where users share their similar experiences and solutions - learn more.

Using these steps should help in resolving the problem with the Yelp app on your iPad.