the walls of your classroom are in motion but appear stationary explain

It all depends on the one who is watching and from where he/she is watching.. If someone from the moon sees the earth or the classroom, it will appear as if the classroom is in motion but for someone who is sitting in the classroom the walls will be stationary because the person sitting in the room moves with the room as well (since the room is located on the earth and the earth is is motion always) but since the person on the moon isn't in motion with the earth, he/she will perceive the walls of the room to be moving..

Hope it helped..