A bus, a falling leaf, a spinning fan — all are moving, but not in the same way. Learn how to precisely describe and measure motion.
Speed tells us how fast an object is moving — the distance covered per unit of time.
A car travels 100 m in 10 s. What is its speed?
Speed = distance/time = 100/10 = 10 m/s
In uniform motion, an object covers equal distances in equal intervals of time (constant speed). In non-uniform motion, the distance covered in equal time intervals varies (the speed is changing).
A car covers 10 m in the first second, 15 m in the second, and 20 m in the third. Is this uniform or non-uniform motion?
Non-uniform motion — the distance covered in each second is increasing, meaning the speed is changing
Distance is the total path length travelled, while displacement is the shortest straight-line distance from the starting point to the ending point, in a specific direction.
If you walk 5 m east and then 5 m back west to your starting point, what is your total distance, and what is your displacement?
Distance = 10 m (total path walked); Displacement = 0 m (you ended up back where you started)
1. A cyclist covers 60 m in 12 s. Find the speed.
2. Does uniform motion mean constant speed or changing speed?
3. A runner covers 8 m in the first second and 12 m in the second second. Is this uniform motion?
4. What is the key difference between distance and displacement?
5. If you walk around a circular track and return to your exact starting point, what is your displacement?