AQA GCSE Combined Science: Trilogy Physics Paper 2 (Foundation), June 2025: Question 6
9 marks · Low Demand difficulty · Short Answer
Calculate speed, resultant force, and interpret motion concepts including distance-time graph gradients and Newton's laws for a dog-sled team.
Practise this questionQuestion
Question text
06 In a dog-sled race, a team of dogs pull on a rope attached to a sled.
Figure 12 shows a dog-sled team.
Figure 12
Use the Physics Equations Sheet to answer questions 06.1 and 06.2.
06.1 What equation links distance travelled, speed and time?
[1 mark]
Tick ( ) one box.
distance travelled = speed × time
speed = time × distance travelled
time = distance travelled × speed 27
06.2 The longest dog-sled race in the world covers a distance of 1 500 000 m.
One team finished the race in a time of 670 000 s.
Calculate the average speed of this team during the race.
[3 marks]
Average speed = m/s
06.3 At the start of the race, 6 dogs pulled on the rope.
The average forward force on the sled from each dog was 370 N.
The backwards force on the sled from friction was 520 N.
Calculate the resultant force on the sled.
[2 marks]
Resultant force = N
Figure 13 shows a distance–time graph for the sled at the start of the race.
Figure 13
06.4 What does the gradient of the graph in Figure 13 represent?
[1 mark]
06.5 Later in the race, the sled moved at a constant speed along a flat, horizontal path.
What was the relationship between the size of the horizontal forces acting when the
sled moved at a constant speed?
[1 mark]
Tick ( ) one box.
friction + air resistance < pull of the rope on the sled
friction + air resistance = pull of the rope on the sled
friction + air resistance > pull of the rope on the sled
0 6*286*
. The rope exerted a force on the sled when the sled was moving.
What is the Newton’s Third Law pair to the force of the rope on the sled?
[1 mark]
Tick ( ) one box.
The force of friction on the sled
The force of the dogs on the rope
The force of the sled on the rope
Mark scheme
Show the mark scheme
Question 6
AO /
Question Answers Extra information Mark
Spec. Ref.
06.1 distance travelled = speed × time 1 AO1
6.5.4.1.2
AO /
Spec. Ref.
06.2 1 500 000 = v × 670 000 1 AO2
6.5.4.1.2
1 500 000 1
v =
670 000
V = 2.2… (m/s) 1
AO /
Spec. Ref.
06.3 F = (6 × 370) - 520 1 AO2
6.5.1.4
F = 1700 (N) 1
if no other mark awarded allow
1 mark for 370 - 520 = (-)150 (N)
AO /
Spec. Ref.
06.4 speed allow velocity 1 AO1
6.5.4.1.4
AO /
Spec. Ref.
06.5 friction + air resistance = pull of the rope on the sled 1 AO1
6.5.1.4
6.5.4.2.1
AO /
Spec. Ref.
06.6 the force of the sled on the rope 1 AO1
6.5.4.2.3
Total Question 6 9
How to answer it
Forces, Motion and Newton's Laws (Dog-Sled Race)
This question assesses your core understanding of Forces and Motion (AQA Topic 5):
- Recalling and rearranging the distance-speed-time equation.
- Calculating resultant forces when multiple forces act in opposite directions.
- Interpreting a distance-time graph (what gradient represents).
- Applying Newton's First Law (balanced forces at constant velocity).
- Identifying Newton's Third Law action-reaction force pairs.
Recalling the Equation for Speed and Distance
1 Mark • AO1 (Recall)
✅ Correct Answer
Tick option 1:
distance travelled = speed × time
🧠 Exam Technique
The question specifies to "Use the Physics Equations Sheet". Always double-check the sheet rather than guessing from memory!
Symbol form: s = v t
Calculating Average Speed
3 Marks • AO2 (Calculation)
📐 Step-by-Step Calculation
- Identify known values:
Distance, s = 1 500 000 m
Time, t = 670 000 s - Substitute values into the equation (Mark 1):
1 500 000 = v × 670 000 - Rearrange to solve for speed, v (Mark 2):
v = 1 500 000 ÷ 670 000 - Calculate the final answer (Mark 3):
v = 2.2388... ≈ 2.2 m/s (or 2.24 m/s )
❌ Common Errors
- Zero counting errors: Missing a zero when typing into the calculator (e.g. entering 150 000 instead of 1 500 000).
- Inverting the division: Calculating time ÷ distance instead of distance ÷ time .
🧠 Exam Tip
Both values were already in standard SI units ( m and s ), so no unit conversion was needed. Always check units first!
Calculating Resultant Force
2 Marks • AO2 (Application)
📐 Step-by-Step Calculation
- Calculate total forward force:
There are 6 dogs, each pulling with 370 N:
Total forward force = 6 × 370 = 2220 N - Calculate resultant force by subtracting backward force:
F = (6 × 370) - 520 (Mark 1)
F = 2220 - 520 = 1700 N (Mark 2)
❌ The "Single Dog" Trap
Many students miss the word each and calculate: 370 - 520 = -150 N .
The mark scheme allows 1 compensation mark if you do this, but you forfeit the second mark. Always re-read the question to check for quantities!
💡 Key Rule: Resultant Force
Forces acting along the same straight line can be added together if in the same direction, or subtracted if acting in opposite directions.
Interpreting a Distance–Time Graph
1 Mark • AO1 (Recall & Graph Skills)
✅ Correct Answer
speed
(Also allowed: velocity)
💡 Why is Gradient = Speed?
Gradient = change in y ÷ change in x
On this graph:
y-axis = distance (m)
x-axis = time (s)
Therefore, Gradient = distance ÷ time = speed .
Newton's First Law: Constant Speed
1 Mark • AO1 (Application of Law)
✅ Correct Answer
Tick option 2:
friction + air resistance = pull of the rope on the sled
💡 Newton's First Law
If an object moves at a constant speed along a straight line, the resultant force must be zero.
This means: Total Backward Forces = Total Forward Forces .
❌ Common Misconception
Students often believe that for an object to be moving forward, the forward force must be larger than resistive forces. That is only true when accelerating (speeding up)!
Newton's Third Law Pairs
1 Mark • AO1 (Recall and Application)
✅ Correct Answer
Tick option 3:
The force of the sled on the rope
🧠 Newton's Third Law "Swap Rule"
Whenever two objects interact, they exert equal and opposite forces on each other:
"Force of A on B" is paired with "Force of B on A"
- Original force: Force of the rope on the sled.
- Third Law pair: Force of the sled on the rope.
Topics
Physics · P5: Forces
Question and mark scheme from the AQA GCSE Combined Science: Trilogy examination, Physics Paper 2 (Foundation), June 2025. QuestionVault is an independent revision resource; questions remain the copyright of the awarding body.