Day 06: Kinematics – Displacement, Velocity, Acceleration
Secondary Stage Science | Apex Institute of Maths and Sciences
Welcome, Scientist! Today we embark on a journey to understand how things move. In Physics, Kinematics is the study of motion without looking at the forces that cause it. We use three magical words to describe any journey:
- Displacement ($s$): The shortest straight-line distance from start to finish.
- Velocity ($v$): How fast you move in a specific direction.
- Acceleration ($a$): The rate at which you speed up or slow down!
| Feature | Distance | Displacement |
|---|---|---|
| Path | Total path taken | Shortest straight line |
| Type | Scalar (No direction) | Vector (With direction) |
To master motion, you need these “Power Formulas.” Use them to calculate your speed or how quickly you’re reaching your destination!
1. Average Velocity: $v = \frac{\Delta s}{\Delta t}$
2. Acceleration: $a = \frac{v – u}{t}$ (where $u$ is starting speed, $v$ is final speed)
- $v = u + at$
- $s = ut + \frac{1}{2}at^2$
- $v^2 = u^2 + 2as$
💡 Tip: If an object starts from rest, $u = 0$. If it stops, $v = 0$.
A bus starts from rest and reaches a velocity of $20\, \text{m/s}$ in $10$ seconds. To find its acceleration, we use $a = (20 – 0) / 10$, giving us $2\, \text{m/s}^2$. That’s how we measure the “pull” you feel when the bus starts!
When a football is kicked, it moves in a straight line. If it travels $10\, \text{meters}$ in $0.5\, \text{seconds}$, its velocity is $20\, \text{m/s}$ toward the goal. Displacement is the gap between the ball and the net!
Walk 5 steps forward, then 3 steps backward.
Observation: What was your total distance? What is your displacement from the starting point? (Hint: They aren’t the same!)
Next time you are in a car, watch the speedometer. When the car turns a corner at the same speed, does its Velocity change?
Hint: Velocity includes direction. If direction changes, velocity changes!
IT is so interesting
I got 10 out of 10