Exam-style question
Try this first
A particle of mass 3 kg has resultant force 33 N. Find the acceleration. Show your working one step at a time.
Model answer
What a good answer should say
- The final answer is 11 m s^-2.
- Use Newton's second law F = ma with a positive direction chosen.
- Set F = 33.
- Set m = 3.
This answer is tied to the objective: R4 Understand and use Newton's third law; use equilibrium of forces on a particle and motion in a straight line, restricted to forces in two perpendicular directions or simple two-dimensional vector cases; apply to smooth pulleys and connected particles; resolve forces in two dimensions; use equilibrium of a particle under coplanar forces..
Explanation
Why this works
Use the explanation to connect the worked answer back to R4 Understand and use Newton's third law; use equilibrium of forces on a particle and motion in a straight line, restricted to forces in two perpendicular directions or simple two-dimensional vector cases; apply to smooth pulleys and connected particles; resolve forces in two dimensions; use equilibrium of a particle under coplanar forces..
exam warm-up keeps the canonical answer 11 m s^-2 fixed before the model answer is written, so the worked solution and final answer agree.
Maths method check
- Topic focus: Mechanics.
- Question style: exam_style.
- Reasoning demand: recall.
- Check the operation, notation, units, and final answer form against the question before moving on.
Common mistake
No common mistake is linked to this question yet.