Study Notes
The equations of motion describe the movement of objects under constant acceleration using four key equations. These equations relate displacement, initial velocity, final velocity, acceleration, and time.
- Displacement — The distance of an object from a fixed point in a specified direction.
Example: If a car moves 10 meters east, its displacement is 10 meters east. - Velocity — The rate of change of displacement, incorporating both magnitude and direction.
Example: A car moving at 60 km/h north has a velocity of 60 km/h north. - Acceleration — The rate of change of velocity, accounting for both magnitude and direction.
Example: A car increasing its speed from 0 to 60 km/h in 10 seconds has an acceleration. - Kinematic Equations — A set of four equations that describe motion under constant acceleration.
Example: v = u + at, where v is final velocity, u is initial velocity, a is acceleration, and t is time.
Exam Tips
Key Definitions to Remember
- Displacement: Distance in a specified direction
- Velocity: Rate of change of displacement
- Acceleration: Rate of change of velocity
- Kinematic Equations: Equations describing motion under constant acceleration
Common Confusions
- Confusing velocity with speed, which does not include direction
- Misunderstanding that acceleration can be negative (deceleration)
Typical Exam Questions
- What is the final velocity of an object after 5 seconds if it starts from rest and accelerates at 2 m/s²? Answer: Use v = u + at, where u = 0, a = 2 m/s², t = 5 s, so v = 10 m/s.
- How do you calculate displacement from a velocity-time graph? Answer: Displacement is the area under the velocity-time graph.
- What does a horizontal line on a velocity-time graph indicate? Answer: It indicates constant velocity.
What Examiners Usually Test
- Ability to apply kinematic equations to solve problems
- Understanding of motion graphs and their interpretations
- Differentiating between scalar and vector quantities