Dropped iPad turns off by itself
if the iPad isn't broken, you are going to need to process a DFU wipe.

unfortunately you will need a computer running a current version of iTunes, if you follow the processes described here:


  
  Connect the device to a computer using a USB cable.
  Hold down both the Home button and Lock button.
  After 8 seconds, release the Lock button while continuing to hold down the Home button.
  If the Apple logo appears, the Lock button was held down for too long.
  Nothing will be displayed on the screen when the device is in DFU mode. If open, iTunes will alert you that a device was detected in
  recovery mode.
  If your device shows a screen telling you to connect the device to iTunes, retry these steps.
  


(Source)