Q: Are there any key words to look for in a problem when trying to figure that out?
A: In general, there are always Key Words that can help you interpret the texts and identify the problems. However, those key words vary from a topic to another. We have to learn how to recognize them through practice problems. Just give an example here: In a motion problem, if it asks to find the velocity (direction/which way and speed/how fast), use the Kinematics. If it just asks the speed/how fast, we would better use the Work/Energy idea.
Q: How are instantaneous velocity and instantaneous speed related to one another?
A: Instantaneous speed is just the magnitude of instantaneous velocity at any time instant.
Q: What is the direction and the magnitude of tension force in a rope generally?
A: In general, tension force always points from the end (contact point with other object) toward the center and the magnitude of tension force remains constant in an ideal (massless) rope/segment.
