Final answer:
The student's question concerns calculating relative velocity in Physics. Relative velocity is computed by subtracting the velocity of one object from another when they are moving directly towards or away from each other. Additional information on vehicle directions is necessary for an accurate calculation in this particular case.
Step-by-step explanation:
The student's question relates to the concept of relative velocity in Physics, specifically within the context of two vehicles traveling in different directions. In the first scenario mentioned in the question, we have vehicles traveling in foggy conditions with given speeds of 70 km/h and 60 km/h. Relative velocity is used to determine the velocity of one object as observed from another object in motion. According to the principle that the relative velocity of an object A with respect to object B is the velocity of A minus the velocity of B (VAB = VA - VB), we can calculate this by converting the speeds from km/h to m/s and then subtracting the slower velocity from the faster one. Therefore, if both vehicles are on a collision course with one being faster than the other, the relative velocity would simply be the difference between their speeds.
In the example provided for reference, the velocity of the car relative to the truck is found by taking the Pythagorean sum of both vehicles' velocities, as they are perpendicular to each other. This is different from the student's scenario where the vehicles are traveling in front of each other.
We also see an example involving average speed, acceleration, and a case involving conservation of momentum in a collision. Each of these illustrates different aspects of kinematics and dynamics in Physics. To precisely answer the student's question, more information is needed regarding the direction of travel for the vehicles involved.