【单选题】You are standing in a moving bus, facing forward, and you suddenly move forward as the bus comes to an immediate stop. What force caused you to move forward?
A.
normal force due to your contact with the floor of the bus
B.
force due to static friction between you and the floor of the bus
C.
force due to kinetic friction between you and the floor of the bus
【简答题】a. remember to write down everything that you have memorized b. understand what you are trying to rememnber c. make sure you get the information correct the first time d. try to test yourself as you m...