Hi, i am studying collisions at school and have a simple question about something i observed while absentmindedly dropping pens. 1)First find a a useless pen (or any other similarly shaped object) and hold it still such that it is parallel to the horizontal about 20 centimeters above your desk and carefully let it fall. If you did it accurately then the whole side of the pen will touch the desk at the same time. 2)Now do the same thing again but this time do it keeping the pen completely vertical witheither side facing down. You probably got what I am getting to- "Why does the center of mass of pen in the second case bounce so high when compared to the first where the pen barely bounces?" Seems strange that velocity of pen in case 2 as it rises is more than that in case 1.(We cant consider it to be point particle???) Possible explanations I thought of- 1)Air resistance in first case when the pen rises is much more than that in the second case. (True but i doubt if that would make such a big difference) 2)I somehow feel that in the 2nd case all the force passes through the center of mass and that somehow makes a difference. (not able to properly explain) 3)Some ideas related to torque which I cant explain as i haven't studied that topic. All ideas and help is appreciated!