Agree. Its okay to not be cheerful at times. Its actually healthy to show emotions.
o que aconteceria se as forças de atração entre todas as partículas da matéria na terra fossem iguais
This is false!
For example, let's take the situation in which you are stressed when you are not prepared for an exam and you have to take the exam. You can plan better your time and start preparing earlier or try to "stage" practice exams for yourself and the result will be less stress!
A. Self-monitoring
I hope this helps your studies!
