Final answer:
False. The scenarios provided blend traffic safety with physics concepts of kinematics. Cars should follow speed limits, with traffic signals aiding in safety. The position vs time graph for an accelerating object is not a straight line, it would show a curve.
Step-by-step explanation:
The question from the student appears to be related to traffic safety and vehicle behavior at intersections and while following routes. However, the given scenarios also blend in concepts from kinematics, which is a branch of physics that deals with the motion of objects without consideration of the causes of the motion.
In terms of the concept discussed, a car moving on a straight road at a constant speed in a single direction exhibits uniform motion, meaning its speed doesn't vary over time. Vehicles at an intersection are expected to adhere to the speed limit and would need to slow down in the presence of a traffic signal, which serves as a safety mechanism.
For the true/false statements provided: It is false that the position vs time graph of an object speeding up is a straight line; such a graph would typically show a curve, representing acceleration. Also, if a person walks in the opposite direction for the second leg of their trip, the magnitude of their total displacement differs from that of the initial plan.