When the palm slaps the glass surface, the applied pressure depends on the slapping force and the area of the palm. Generally speaking, the area of the palm is about 10-20 square centimeters, and the flapping strength varies from person to person. So the pressure applied when tapping the glass surface is very small, maybe only a few cows.
If a hard tool (such as a rubber hammer) is used, the applied pressure will be greater, depending on the quality of the tool and the strength of the user. Generally speaking, when you hit the glass surface with a rubber hammer, the pressure applied is generally between10-50 N. In addition, you should also pay attention to the thickness and material of the glass when you hit the glass surface. The greater the thickness of the glass, the greater the pressure it can withstand; Different materials of glass have different strengths and can withstand different pressures.