Tracking Movement: Motion (Kinematics)
Kinematics describes and analyzes motion in terms of displacement, velocity, and acceleration, without considering the forces causing it, providing a framework to understand how objects move. Displacement measures the change in position, velocity tracks the rate of that change, and acceleration captures how velocity changes over time, enabling precise predictions of motion in scenarios like a car speeding up or a ball rolling down a hill.
Overview of Motion (Kinematics)
Kinematics is defined by the key quantities that characterize motion. Here’s the breakdown:
- Displacement: The change in an object’s position, a vector quantity with direction.
- Velocity: The rate of change of displacement, including speed and direction.
- Acceleration: The rate of change of velocity, showing how quickly motion speeds up or slows down.
- Motion Equations: Formulas linking displacement, velocity, acceleration, and time to analyze motion.
Examples of Motion (Kinematics)
Displacement Examples
- A car moves 50 meters east from its starting point.
- A runner finishes 10 meters south of her initial position.
- A ball rolls 5 meters downhill on a ramp.
Velocity Examples
- A bike travels at 10 m/s north along a straight path.
- A plane flies at 200 m/s eastward during a flight.
- A swimmer moves at 2 m/s downstream in a river.
Acceleration Examples
- A car speeds up from 0 to 20 m/s in 4 seconds, accelerating at 5 m/s².
- A ball slows from 15 m/s to 5 m/s in 2 seconds, decelerating at -5 m/s².
- A rocket increases velocity from 100 m/s to 300 m/s in 10 seconds, accelerating at 20 m/s².
Motion Equations Examples
- Using v = u + at: A car with initial velocity 0 m/s accelerates at 3 m/s² for 5 s, reaching 15 m/s.
- Using s = ut + ½at²: A ball dropped (u = 0) with a = 9.8 m/s² falls 4.9 m in 1 s.
- Using v² = u² + 2as: A bike (u = 10 m/s, a = -2 m/s²) stops (v = 0) after traveling 25 m.