CIRCULAR TRACK & MEETING PROBLEMS CORE CONCEPT
When two or more people move on a circular track, they start from the same point and move in the same or opposite directions. We need to find when they meet again, how many times they meet, or their relative speeds. This is different from linear track problems because the track repeats — people can meet multiple times at different points. KEY RULES & PROPERTIES
1. Same Direction Meeting: Person A and B start together. A is faster. A will lap (overtake) B when A covers exactly one full lap MORE than B. They meet again when the faster person gains a full circle's distance on the slower one. 2. Opposite Direction Meeting: They are moving towards each other. They meet every time their combined distance equals the track length.
3. Relative Speed Concept: In same direction, relative speed = (Speed of faster person) - (Speed of slower person). In opposite direction, relative speed = (Speed of person 1) + (Speed of person 2). 4. Time Between Meetings: This stays constant for each meeting if speeds are constant.
Same direction (A catches B):
Opposite direction:
• They meet again at same time intervals after the first meeting
Two persons on circular track, find when they meet next
How many times do they meet in a given time?
At what point on the track do they meet?
Relative speed and time calculation problems SHORTCUT/TRICK "For same direction problems: Just find how long it takes for the faster person to gain one full lap. That's your meeting time. Multiply by the number you need."
Since they're moving in the same direction, relative speed = 10 - 6 = 4 m/s
For A to meet B again, A must gain exactly one full lap = 400m
Time = Distance / Speed = 400 / 4 = 100 seconds
They meet again after 100 seconds. Verification: In 100 seconds, A covers = 10 × 100 = 1000m = 2 full laps + 200m. B covers = 6 × 100 = 600m = 1 full lap + 200m. Both are at the same point (200m mark). ✓
Students often forget that in SAME direction, you subtract speeds. They wrongly add speeds (which is for opposite direction only). This leads to completely wrong answers.
Always check the direction first.
15graded MCQs · easy to hard · full solution & trap analysis