Some glasses break when you pour boiling water in it. To avoid that make sure you read a label that comes with that glass saying it can withstand boiling water or not.
You can break your fast at sunset.
No, crying does not break a fast.
No, ejaculating does not break a fast.
No, ejaculation does not break a fast.
No, precum does not break a fast.
A fast change in temperature same reason boiling water will freeze if its below 32 and you throw it in the air.
You need to know the area of the glass, its span, how it is supported, and how thick it is; also you need to know the stiffness of the tennis ball; so this is a complex problem.
Glass can break when exposed to certain frequencies, such as those produced by a singer with a very strong and sustained voice. If the pitch of the sound waves matches the natural frequency of the glass, it can cause the glass to vibrate excessively and ultimately shatter due to this resonance phenomenon.
Thermal shock. As one part of the crystal expands quicker than the other (the inside and outside), they will eventually tear apart and cause the cracking. If it occurs fast enough, it may even make the glass explode from the stresses applied.
Glass does not typically "break" at any temperature. If you want to be technical, the melting point of glass is 2600-2900 °F. Now, another important and relevant fact is that when things are hot, they grow very slightly larger due to their molecular composition. When something is very hot and is suddenly made much cooler, it will quickly shrink back to normal. When fragile things like glass are cooled down too fast, the shape change is enough to crack or break them.
boiling water
No, hugging a girl does not break your fast.