Part 1 - Multiple Choices and short answer questions. No need to show work 1. (4 pts) These four motion diagrams show the motion of a particle along the x-axis. The positive direction points toward right, For the following four motions diagrams, put a "+" sign to the motion with a positive acceleration and a "-" sign to the motion with a negative acceleration. Start (a) Start (b) Start (c) Start (d)