A-Level · Mathematics · AQA · Mark scheme decoded
AQA A-Level Mathematics: Kinematics Language and Concepts — mark scheme explained
The short answer
Kinematics is the branch of physics that deals with the motion of objects without considering the forces that cause the motion. In AQA A-Level Mathematics, understanding and using the language of kinematics is crucial for solving problems related to motion.
The question
A car travels from point A to point B, which are 100 meters apart. It then returns to point A. Calculate the total distance travelled and the displacement of the car. [Paraphrased for study — not reproduced from any exam paper.]
Mark scheme, decoded
What each mark is really for — in plain English — and the wording trap that loses it.
- S1
The car travels from point A to point B, a distance of 100 meters.
- S2
It then returns to point A, another 100 meters.
- S3
Total distance travelled = 100 meters + 100 meters = 200 meters.
- S4
Displacement is the change in position from the initial to the final point. Since the car returns to its starting point, displacement = 0 meters.
Model answer
Worked through, with each step tagged to the mark it earns.
- S1
The car travels from point A to point B, a distance of 100 meters.
- S2
It then returns to point A, another 100 meters.
- S3
Total distance travelled = 100 meters + 100 meters = 200 meters.
- S4
Displacement is the change in position from the initial to the final point. Since the car returns to its starting point, displacement = 0 meters.
Final answer: Distance travelled: 200 meters; Displacement: 0 meters
Common mistakes
- Confusing displacement with distance travelled. — Always consider the direction of motion when calculating displacement and use the total path length for distance travelled.
- Using speed instead of velocity in vector calculations. — Ensure you use the appropriate formula and consider the direction when dealing with velocity.
- Forgetting to include units in answers. — Always include the appropriate units (e.g., meters, seconds) in your final answers.
- Incorrectly interpreting graphs. — Practice identifying what different parts of the graph represent (slope for velocity, area for displacement).
- Using incorrect formulas for kinematic equations. — Memorize the key kinematic equations and practice applying them in different scenarios.
- Neglecting negative signs in vector quantities. — Always pay attention to the sign of vector quantities and include them in your calculations.
Where the marks go
- Full worked solution (all marking points)4 marks