AQA A-Level Physics Paper 1, June 2023: Question 24
1 mark · Medium difficulty · Multiple Choice
Determine how doubling the mass of a trolley moving down a slope affects its accelerating force or acceleration, given negligible air resistance and friction.
Practise this questionQuestion
Question text
24 A trolley moves down a slope with constant acceleration.
The mass of the trolley is doubled and the trolley moves down the same slope again.
Air resistance and friction are negligible.
Which is correct?
[1 mark]
A The accelerating force is unchanged.
B The accelerating force is halved.
C The acceleration is unchanged.
D The acceleration is halved.
Mark scheme
Show the mark scheme
24 C The acceleration is unchanged.
How to answer it
Trolley Acceleration Down a Slope
This question assesses your understanding of Newton's Second Law of Motion ( F = ma ), resolving forces on an inclined plane, and recognizing how mass affects acceleration when gravitational force is the sole driver.
Question 24
Multiple Choice Component
✅ Correct Answer: C
The acceleration is unchanged.
When the mass is doubled, the component of weight acting down the slope also doubles. Because F = ma , doubling both the force and the mass leaves the resulting acceleration completely unaffected ( a = F / m ).
💡 Key Knowledge
- The accelerating force down a frictionless slope is given by F = mg sin(θ) .
- Newton's Second Law states a = F / m .
- Substituting the force into the acceleration equation gives a = (mg sin(θ)) / m . The mass m cancels out!
🧠 Exam Technique
Don't be fooled by everyday intuition! Many students assume heavier objects accelerate slower or faster. Always write out the algebraic relationship first to see if variables cancel out before choosing your answer.
❌ Common Errors
- Choosing B or D: Assuming that doubling the mass halves the acceleration because they misapplied inverse proportionality without checking the force term.
- Choosing A: Forgetting that the accelerating force is weight component ( mg sin(θ) ), which *does* change when mass changes.
Topics
Physics · 3.4 Mechanics and materials
Question and mark scheme from the AQA A-Level Physics examination, Paper 1, June 2023. QuestionVault is an independent revision resource; questions remain the copyright of the awarding body.