teachers in japan stil use physical violence ?

Only in Gensoukyou

I'm reminded of Cirno's perfect math class where Keine headbutts Cirno.
"Yukkuri Shiteitte ne!"

Lol, nice male uniform there Wriggle

Rumia seems surprised, but it looks like it's not towards the massive head-butt action going on. She's holding and looking at something in her right hand instead. Would look like as if it's a cellphone.

You sure that's not her bento? Looks like she could be holding chopsticks there.

She's not surprised, she's vigorously eating pocky.

Or her pencils.

At least they didn't sign up for night classes.