Mark Scheme
Section A — Structured Questions
Question 1
(a) [1 mark]
- Stand clear when adding masses / wear safety goggles / use a clamp to secure stand / place cushion under spring / ensure masses are secure
- Accept any one sensible safety precaution
(b) [2 marks]
- Extension is (directly) proportional to weight OR extension increases linearly with weight [1]
- up to a weight of 4.0 N / for the first four results / until the limit of proportionality is reached [1]
- Accept: "up to 0.40 kg"
(c) [3 marks]
Method:
- k = F / e OR rearrangement of F = ke [1]
- Correct substitution, e.g., k = 4.0 / 0.10 OR k = 2.0 / 0.05 [1]
- k = 40 N/m [1]
Accept values from 39 to 41 N/m if working shown
Award 2 marks for correct answer with no working
(d) [2 marks]
- The spring has exceeded its limit of proportionality / elastic limit [1]
- (so) extension is no longer proportional to force / spring begins to deform plastically / larger extensions occur for the same increase in force [1]
Question 2
(a) [4 marks]
Award 1 mark for each correct energy transfer, maximum 4:
- Chemical (potential) energy in coal
- Transferred to thermal energy / heat energy (by combustion / burning)
- (Thermal energy) transferred to kinetic energy in steam / turbine
- Kinetic energy transferred to electrical energy (in generator)
- Accept: internal energy for thermal energy
- Do not accept: heat on its own
(b) [3 marks]
- efficiency = useful output / total input OR 0.38 = 2000 / input [1]
- Rearrangement: input = 2000 / 0.38 [1]
- = 5263 MW OR 5300 MW (to 2 s.f.) [1]
Accept answers from 5200 to 5270 MW
(c) [4 marks]
- Vₚ Iₚ = Vₛ Iₛ (for 100% efficient transformer) [1]
- 25,000 × 3200 = 400,000 × Iₛ OR Iₛ = (25 × 3200) / 400 [1]
- = 200 A (if 100% efficient) [1]
- Correction for 98% efficiency: 200 × 0.98 = 196 A OR 200 A / 0.98 = 204 A in secondary [1]
Accept either 196 A or 204 A for final mark depending on approach
(d) [3 marks]
- High potential difference means lower current (for the same power) [1]
- Lower current means less energy lost as heat / lower I²R losses [1]
- (Therefore) transmission is more efficient / less energy wasted [1]
Question 3
(a) [2 marks]
- GPE = mgh OR GPE = 0.50 × 9.8 × 2.0 [1]
- = 9.8 J [1]
(b) [3 marks]
- GPE transferred to KE: ½mv² = mgh OR ½mv² = 9.8 [1]
- v² = 2gh OR v² = (2 × 9.8) / 0.5 OR v² = 39.2 [1]
- v = 6.3 m/s OR 6.26 m/s [1]
Accept answers from 6.2 to 6.3 m/s
(c) [2 marks]
- Energy is transferred to thermal energy / heat [1]
- (Caused by) deformation of ball / friction / air resistance / sound [1]
Do not accept "lost" or "destroyed" without further qualification
(d) [2 marks]
- Second ball rebounds to greater height / 1.8 m vs 1.6 m [1]
- (Therefore) second ball transfers less energy as thermal energy / second ball is more elastic / stores more elastic potential energy [1]
Question 4
(a) [2 marks]
- a = Δv / t OR a = (20 - 0) / 5 [1]
- = 4 m/s² [1]
(b) [3 marks]
Award 1 mark for each section:
- First section (0-5s): ½ × 5 × 20 = 50 m [1]
- Second section (5-15s): 10 × 20 = 200 m [1]
- Third section (15-20s): ½ × 5 × 20 = 50 m [1]
- Total = 300 m
Award all 3 marks for correct answer of 300 m with no working
(c) [2 marks]
- F = ma OR F = 1200 × 4 [1]
- = 4800 N [1]
(d) [3 marks]
- KE = ½mv² = ½ × 1200 × 20² = 240,000 J [1]
- Work done = force × distance OR 240,000 = F × 50 [1]
- F = 4800 N [1]
Accept: use of v² = u² + 2as to find deceleration, then F = ma
(e) [2 marks]
Award 1 mark for each factor, maximum 2:
- Greater speed / higher velocity (of car)
- Poor road conditions / wet / icy / loose surface
- Poor tire condition / worn tires / under-inflated tires
- Poor brakes / worn brake pads
- Greater mass / heavier load
Do not accept: reaction time (this affects thinking distance, not braking distance)
Question 5
(a) [2 marks]
- R = V / I OR R = 4.5 / 0.015 [1]
- = 300 Ω [1]
(b) [4 marks]
Resistance of LDR:
- Resistance increases [1]
- Because less light falls on the LDR / light intensity decreases [1]
Voltmeter reading:
- Voltmeter reading increases [1]
- Because resistance of LDR increases, so greater share of voltage / larger proportion of p.d. across LDR [1]
(c) [1 mark]
Accept any one sensible application:
- Automatic street lighting
- Camera exposure control
- Solar panels / solar trackers
- Automatic dimming of displays
- Greenhouse monitoring
Question 6
(a) [1 mark]
(Total nucleon numbers: 236 = 144 + 89 + X, therefore X = 3)
(b) [2 marks]
- (Some) mass is converted into energy [1]
- According to E = mc² / mass-energy equivalence [1]
Accept: mass defect occurs
(c) [2 marks]
- Neutrons released from fission go on to cause further fission reactions [1]
- (Creating) a self-sustaining reaction / each fission triggers more fissions [1]
(d) [3 marks]
Function:
- (Control rods) control the rate of fission / control the reaction [1]
How they work:
- (Control rods) absorb neutrons [1]
- Lowering them in increases absorption / slows reaction; raising them decreases absorption / speeds up reaction [1]
(e) [4 marks]
Advantages (of nuclear fission):
- No CO₂ / greenhouse gases produced during operation
- Large amount of energy from small amount of fuel
- Does not contribute to climate change / global warming
- Fuel (uranium) is relatively abundant
Disadvantages (of nuclear fission):
- Produces radioactive waste that is dangerous for thousands of years
- High initial building costs / decommissioning costs
- Risk of accidents with serious consequences
- Long construction time
- Public concerns / planning issues
Award marks for:
- One advantage clearly stated [1]
- Second advantage clearly stated [1]
- One disadvantage clearly stated [1]
- Second disadvantage clearly stated [1]
Accept converse points for fossil fuels
Accept developed points for same factor
Section B — Extended Response
Question 7 [12 marks]
This is a levels-based question. Award marks using the levels of response criteria below.
Level 3 (9-12 marks):
- Comprehensive evaluation covering economic, environmental, and practical factors
- Detailed analysis with relevant calculations or quantitative comparisons
- Clear comparison drawn between the two options
- Reasoned conclusion or judgment reached
- Answer is coherent, logical, and well-structured
- Specialist terminology used appropriately
Level 2 (5-8 marks):
- Some evaluation of economic, environmental, and/or practical factors
- Some attempt at comparison or quantitative reasoning
- Partial conclusion or limited judgment
- Answer has some logical structure
- Some use of specialist terminology
Level 1 (1-4 marks):
- Basic statements about one or more factors
- Little or no comparison
- No clear conclusion
- Answer lacks coherent structure
- Limited use of specialist terminology
0 marks: No relevant content
Indicative content:
Economic factors:
- Higher initial cost (£42,000 vs £28,000 = £14,000 more)
- Lower running costs: at 25,000 km/year: electric = £800/year, diesel = £2,375/year (saving £1,575/year)
- Lower service costs (£180 vs £450 = saving £270/year)
- Total annual saving of approximately £1,845/year
- Battery replacement (£6,500 after 8 years) must be factored in
- Payback period calculation (approximately 7-8 years)
Environmental factors:
- Zero direct emissions from electric vans
- However, electricity generation may produce CO₂ (depends on source)
- Diesel van produces 145 g CO₂/km = 3.625 tonnes CO₂/year
- Environmental regulations / clean air zones may restrict diesel vehicles
- Corporate social responsibility / company image
Practical considerations:
- Range limitation of electric van (250 km vs 800 km)
- Need for more frequent charging
- Charging infrastructure required / availability of charging points
- Charging time vs refueling time
- Suitability depends on typical delivery routes
- If daily routes less than 250 km, electric is viable
Accept other relevant points
Question 8 [14 marks]
This is a levels-based question. Award marks using the levels of response criteria below.
Level 3 (10-14 marks):
- Comprehensive analysis of all stages of motion
- Clear explanation of forces at each stage linked to velocity changes
- Correct application of Newton's laws throughout
- Detailed explanation of terminal velocity concept (at two different speeds)
- All physics is correct with appropriate use of specialist terminology
- Answer is coherent, logical and well-structured
Level 2 (5-9 marks):
- Description of several stages with some explanation of forces
- Some application of Newton's laws
- Some reference to terminal velocity
- Most physics is correct
- Answer has some logical structure with some appropriate terminology
Level 1 (1-4 marks):
- Basic description of motion or forces
- Limited or no application of Newton's laws
- Little understanding of terminal velocity
- Answer lacks coherent structure
- Limited specialist terminology
0 marks: No relevant content
Indicative content:
Stage 1 (0 to 15 s):
- Velocity increases (in downward direction) / acceleration downward
- Weight force acts downward (constant)
- Air resistance acts upward (increasing as speed increases)
- Resultant force downward (but decreasing) because weight > air resistance
- Newton's second law: resultant force causes acceleration
- Acceleration decreases as air resistance increases
- Approaching terminal velocity
Stage 2 (15 to 60 s):
- Constant velocity / zero acceleration
- First terminal velocity reached (approximately 55 m/s)
- Weight = air resistance / balanced forces / zero resultant force
- Newton's first law: object continues at constant velocity when forces balanced
- Air resistance proportional to (velocity)²
Stage 3 (at 60 s):
- Sudden decrease in speed / large upward acceleration
- Parachute opens
- Large increase in air resistance / drag force increases dramatically
- Air resistance now much greater than weight
- Large resultant upward force causes large upward acceleration (deceleration)
Stage 4 (60 to 100 s):
- Velocity increases downward (but slowly) / small downward acceleration
- Weight > air resistance (but forces becoming closer)
- Resultant downward force decreases
- Air resistance increasing as velocity increases
- Approaching second terminal velocity
Stage 5 (100 to 115 s):
- Second terminal velocity reached (approximately 8 m/s)
- Much slower than first terminal velocity
- Weight = air resistance again / forces balanced
- Newton's first law applies: constant velocity
- Air resistance greater (for given speed) due to larger surface area of parachute
Stage 6 (115 s onwards):
- Velocity decreases to zero
- Lands on ground
- Ground reaction force / normal contact force acts upward
- Upward resultant force decelerates skydiver to rest
Question 9
(a) [2 marks]
- E = mcΔθ OR E = 150 × 4200 × (42 - 15) [1]
- = 17,010,000 J OR 17.01 MJ OR 1.7 × 10⁷ J [1]
Accept answers from 16,800,000 to 17,100,000 J
(b) [2 marks]
- Power = intensity × area = 800 × 2.0 = 1600 W [1]
- Energy = power × time = 1600 × (4 × 3600) = 23,040,000 J OR 23.04 MJ [1]
Accept 23,000,000 J or 2.3 × 10⁷ J
(c) [2 marks]
- Efficiency = useful output / total input OR = 17,010,000 / 23,040,000 [1]
- = 0.738 OR 73.8% OR 74% [1]
Accept answers from 0.73 to 0.75 or equivalent percentages
(d) [8 marks]
This is a levels-based question. Award marks using the levels of response criteria below.
Level 3 (7-8 marks):
- Detailed explanation of all three design features
- Clear links made between each feature and specific heat transfer processes
- Correct physics throughout with appropriate specialist terminology
- Answer is coherent and well-structured
Level 2 (4-6 marks):
- Explanation of two or three design features
- Some links to heat transfer processes
- Most physics is correct
- Some appropriate specialist terminology
Level 1 (1-3 marks):
- Basic description of one or more features
- Limited reference to heat transfer processes
- Answer lacks structure
- Limited specialist terminology
0 marks: No relevant content
Indicative content:
Black painted pipes:
- Black surfaces are good absorbers of (infrared) radiation
- Black surfaces absorb more thermal radiation than light/shiny surfaces
- Maximum absorption of solar energy / radiation
- Thermal energy transferred to water by conduction (through pipe wall)
Glass cover with air gap:
- Glass is transparent to (visible) light / short wavelength radiation
- Allows sunlight to pass through to pipes
- Glass absorbs / reflects infrared / long wavelength radiation
- Reduces thermal energy loss by radiation (from hot pipes)
- Air gap reduces thermal energy loss by conduction
- Air is a poor conductor / insulator
- Reduces convection losses / convection cannot occur in trapped air
- Greenhouse effect / traps heat
Insulation at back:
- Insulation reduces thermal energy loss by conduction
- Insulation contains trapped air
- (Trapped) air is poor conductor / good insulator
- Reduces heat transfer to surroundings
- Keeps thermal energy in the system
- May also reduce convection
Accept other relevant physics related to heat transfer (conduction, convection, radiation)
Sample Answers with Examiner Commentary
Question 7 — Sample Answers
Grade 9 (top of Higher) answer
The transport company should carefully evaluate multiple factors before making this decision.
Economic analysis:
The electric van costs £14,000 more initially (£42,000 vs £28,000). However, running costs are significantly lower. For 25,000 km per year, the diesel van costs £9.50 per 100 km, which equals £2,375 per year for fuel. The electric van costs £3.20 per 100 km, which equals £800 per year for electricity. This is an annual saving of £1,575 on fuel alone.
Service costs are also lower for electric vans: £180 per year compared to £450 for diesel, saving an additional £270 per year. The total annual saving is therefore £1,845.
However, the battery replacement cost of £6,500 after 8 years must be considered. Over 8 years, total savings would be approximately £14,760, which would cover the higher initial cost and the battery replacement (total extra cost = £20,500). The break-even point would be approximately 11 years.
Environmental factors:
The electric van produces zero direct emissions, whereas the diesel van produces 145 g CO₂/km. At 25,000 km per year, this equals 3,625 kg or 3.6 tonnes of CO₂ annually. Over the vehicle's lifetime, this represents a significant environmental impact. However, the true environmental benefit depends on how the electricity is generated - if from coal-fired power stations, there are still indirect emissions, though generally lower overall. Increasingly, renewable energy is being used, making electric vehicles cleaner. Additionally, clean air zones in many cities now charge or ban diesel vehicles, which could affect operations.
Practical considerations:
The critical factor is the range. The diesel van can travel 800 km on a full tank, while the electric van only 250 km. For delivery routes, this depends on daily mileage. If the typical daily route is under 200 km, the electric van would be suitable and could be charged overnight. However, if longer routes are required, the electric van would need recharging during the day, adding significant time. The company would also need to install charging infrastructure at their depot and drivers would need access to public charging points.
Conclusion:
If the company's delivery routes are typically under 200 km per day, the switch to electric vans would be economically viable in the long term (after approximately 11 years), significantly better environmentally, and practically feasible. However, if longer range is regularly required, the practical limitations would outweigh the benefits. The company should analyze their actual daily mileage patterns before making a decision. They might also consider a mixed fleet approach, using electric vans for urban deliveries and diesel for longer routes.
Mark: 12/12
Examiner commentary: This is an exemplary Level 3 response. The student provides comprehensive evaluation of all three required factors with detailed quantitative analysis. Economic calculations are accurate and relevant (annual savings, break-even analysis). Environmental factors are discussed with specific figures and critical evaluation of indirect emissions. Practical considerations are thoroughly explored with clear reasoning about suitability. The answer reaches a balanced, evidence-based conclusion. Specialist terminology is used accurately throughout and the response is exceptionally well-structured. This demonstrates the analytical thinking and comprehensive evaluation required for top marks.
Grade 6 (solid pass) answer
Economic factors:
The electric van costs more to buy - £42,000 compared to £28,000 for diesel. But the running costs are cheaper. The electric van costs £3.20 per 100 km while diesel costs £9.50 per 100 km. If the van travels 25,000 km per year, the electric van will cost £800 per year and diesel will cost £2,375 per year. This saves £1,575 per year on fuel. Service costs are also lower at £180 for electric compared to £450 for diesel, saving another £270 per year.
However, the battery needs replacing after 8 years which costs £6,500. This is expensive.
Environmental factors:
Electric vans produce no CO₂ emissions which is better for the environment. The diesel van produces 145 g/km of CO₂. This causes climate change and global warming. Electric vans are cleaner and better for air quality in cities. Some cities are banning diesel vehicles because of pollution.
Practical factors:
The main problem is the range. The electric van can only go 250 km before needing to recharge, but the diesel van can go 800 km. This means the electric van needs charging more often which takes time. If the delivery routes are short, under 250 km per day, then the electric van would work. But if they need to travel further, the diesel van would be better.
The company would need to install chargers at their depot.
Conclusion:
Overall, I think the electric van would be good for short delivery routes because it saves money on fuel and is better for the environment, even though it costs more to buy.
Mark: 7/12
Examiner commentary: This is a solid Level 2 response that addresses all three required factors but with less depth than the top answer. The economic analysis includes some relevant calculations (annual fuel costs correctly calculated) but doesn't calculate break-even period or total cost over vehicle lifetime. Environmental discussion identifies the key benefit (zero direct emissions) and makes valid points about air quality and city restrictions, but lacks the quantitative detail (total annual CO₂ from diesel) and doesn't discuss indirect emissions from electricity generation. Practical factors are mentioned but not fully explored. The conclusion is present but basic. To reach Level 3, this answer needs more detailed quantitative analysis, more sophisticated comparison, and deeper critical evaluation.
Grade 3 (near miss) answer
Electric vans are better for the environment because they don't produce any pollution. Diesel vans create CO₂ which causes global warming. Electric vans are cleaner and don't damage the atmosphere.
The electric van costs more to buy at £42,000 compared to £28,000 for the diesel van. That's £14,000 more which is a lot of money. But the electricity is cheaper than diesel fuel. Electric vans cost £3.20 per 100 km and diesel costs £9.50 per 100 km, so you save money on fuel.
The problem with electric vans is they can't go as far. They can only go 250 km but diesel vans can go 800 km. This means you have to keep stopping to charge them up which wastes time. Charging takes a long time compared to filling up with diesel.
I think they should buy electric vans because they are better for the environment and they save money on fuel.
Mark: 4/12
Examiner commentary: This is a basic Level 1 response. The student makes some valid points but lacks the detail, structure, and analytical depth required for higher marks. The environmental benefit is stated but not explained quantitatively (no calculation of annual CO₂ emissions). The economic discussion identifies the higher purchase price and lower running costs but provides no calculations of annual savings, payback period, or consideration of service costs and battery replacement. The practical limitation is mentioned (range) but not evaluated in context (suitability depends on route length). The conclusion is present but not justified with evidence or balanced evaluation. To improve, this answer needs: quantitative analysis with calculations; consideration of all factors from the table; balanced evaluation rather than one-sided argument; and a reasoned conclusion based on evidence. The student also doesn't consider the suitability depends on actual usage patterns - a key practical factor.
Question 8 — Sample Answers
Grade 9 (top of Higher) answer
Stage 1 (0-15 seconds): Initial acceleration
When the skydiver first jumps from the aircraft, she accelerates downward. Two forces act on her: her weight (which is constant throughout at W = mg) acting downward, and air resistance acting upward. Initially, air resistance is zero or very small because her velocity is low.
According to Newton's second law (F = ma), the resultant downward force causes downward acceleration. As her velocity increases, air resistance increases because air resistance is proportional to velocity squared (or speed squared). This means the resultant downward force (weight minus air resistance) decreases, so the acceleration decreases. This is shown on the graph by the curve flattening as she approaches 55 m/s. She is accelerating but at a decreasing rate.
Stage 2 (15-60 seconds): First terminal velocity
At 15 seconds, the skydiver reaches her first terminal velocity of approximately 55 m/s. At this point, the velocity is constant, which means acceleration is zero. This occurs because air resistance has increased to equal her weight. According to Newton's first law, when forces are balanced (zero resultant force), an object continues to move at constant velocity. The skydiver continues to fall at 55 m/s with no acceleration because the upward air resistance force equals the downward weight force.
Stage 3 (at 60 seconds): Parachute opens
At 60 seconds, there is a sudden decrease in speed shown by the velocity changing rapidly from 55 m/s to approximately 5 m/s. This is when the parachute opens. The parachute has a very large surface area, which dramatically increases the air resistance. The air resistance force suddenly becomes much greater than the weight force, creating a large upward resultant force. According to Newton's second law, this resultant upward force causes upward acceleration (or deceleration in the direction of motion). This large deceleration slows the skydiver rapidly.
Stage 4 (60-100 seconds): Approaching second terminal velocity
After the parachute opens and the skydiver has slowed to about 5 m/s, she still has a slight downward acceleration as shown by the curve from 60 to 100 seconds. At 5 m/s, the air resistance has decreased because it depends on speed squared. Now the weight force is slightly greater than the air resistance again, so there is a small resultant downward force causing slight downward acceleration. As the velocity increases from 5 m/s toward 8 m/s, the air resistance increases again.
Stage 5 (100-115 seconds): Second terminal velocity
At 100 seconds, the skydiver reaches a second terminal velocity of approximately 8 m/s. Again, the forces are balanced - weight equals air resistance - so there is zero resultant force and therefore zero acceleration. The velocity remains constant at 8 m/s. This terminal velocity is much slower than the first terminal velocity (8 m/s compared to 55 m/s) because the parachute creates much more air resistance at any given speed due to its large surface area. Even at the lower speed of 8 m/s, the air resistance is sufficient to balance the weight.
Stage 6 (115 seconds onward): Landing
At 115 seconds, the velocity rapidly decreases to zero as the skydiver lands on the ground. The ground exerts an upward reaction force (normal contact force) on the skydiver. This large upward force, combined with the continuing upward air resistance, creates a large upward resultant force that decelerates the skydiver to rest very quickly.
Throughout the entire fall, the weight force remains constant, but air resistance changes depending on the velocity and the surface area (whether the parachute is open or closed). The motion is entirely explained by Newton's laws and the relationship between air resistance and velocity.
Mark: 14/14
Examiner commentary: This is an outstanding Level 3 response that comprehensively addresses all aspects of the question. Each stage of motion is clearly identified and explained. The forces at each stage are correctly described with explicit reference to Newton's first and second laws. The answer demonstrates sophisticated understanding of terminal velocity, correctly explaining why it occurs twice at different speeds and relating this to the balance of forces and the relationship between air resistance and velocity. The physics terminology is used precisely throughout (resultant force, acceleration, deceleration, balanced forces). The structure is logical and coherent, working systematically through each stage. This demonstrates the depth of analysis and application of physics principles required for full marks.
Grade 6 (solid pass) answer
Stage 1 (0-15 seconds):
At the start, the skydiver accelerates downward because her weight pulls her down. Air resistance acts upward but is small at first. The resultant force is downward so she accelerates. As she goes faster, air resistance increases. The graph shows the velocity increasing but the curve gets flatter, which means the acceleration is decreasing. This is because air resistance is getting bigger as she speeds up.
Stage 2 (15-60 seconds):
The velocity stays constant at 55 m/s. This is terminal velocity. Terminal velocity happens when air resistance equals weight, so the forces are balanced. When forces are balanced there is no acceleration, so velocity stays constant. This is Newton's first law.
Stage 3 (60 seconds):
The parachute opens at 60 seconds. This causes the velocity to suddenly decrease from 55 m/s to about 5 m/s. The parachute creates lots of air resistance because it has a big surface area. The air resistance is now bigger than weight, so there is a resultant force upward. This causes the skydiver to slow down rapidly.
Stage 4 (60-100 seconds):
After the parachute opens, the velocity slowly increases again from 5 m/s to 8 m/s. The weight is slightly bigger than air resistance, so there is a small resultant force downward. This causes a small acceleration downward.
Stage 5 (100-115 seconds):
The velocity becomes constant again at 8 m/s. This is a second terminal velocity. The forces are balanced again with air resistance equaling weight. This terminal velocity is slower than the first one because the parachute creates more air resistance.
Stage 6 (115 seconds):
The skydiver lands and the velocity goes to zero. The ground pushes up on the skydiver, creating a force that stops her.
Overall, the motion is controlled by the balance between weight pulling down and air resistance pushing up. Terminal velocity occurs when these forces are equal.
Mark: 8/14
Examiner commentary: This is a good Level 2 response that demonstrates sound understanding of the key concepts. All stages are identified and there is correct explanation of terminal velocity and force balance. Newton's first law is explicitly mentioned. However, the response lacks the depth and precision of a Level 3 answer. The explanations are sometimes brief (e.g., stage 6 needs more detail about reaction forces). Newton's second law is implied but not explicitly stated. The relationship between air resistance and velocity (proportional to v²) is not mentioned. The answer would benefit from more detailed force analysis at each stage and more explicit linking to Newton's laws throughout. The explanation of why the second terminal velocity is lower is correct but could be developed further. Overall, this shows good physics understanding but needs more sophistication and depth of analysis to reach the highest level.
Grade 3 (near miss) answer
When the skydiver jumps out of the plane, she falls down because of gravity. She goes faster and faster at first. The graph shows her speed increasing up to 55 m/s.
Then her speed stays the same at 55 m/s for a while. This is called terminal velocity. Terminal velocity is when you stop accelerating and go at the same speed. This happens because air resistance gets bigger as you go faster. Eventually air resistance becomes equal to gravity so you stop speeding up.
At 60 seconds, the parachute opens. This makes the speed suddenly drop to 5 m/s. The parachute catches lots of air which slows you down. Parachutes have lots of air resistance.
After the parachute opens, the speed goes up a bit to 8 m/s and then stays constant. This is terminal velocity again but slower because the parachute is open.
At 115 seconds the skydiver lands on the ground and stops moving.
The forces acting on the skydiver are gravity pulling down and air resistance pushing up. When these are equal you get terminal velocity. When air resistance is smaller than gravity you accelerate down. When air resistance is bigger than gravity you slow down.
Mark: 4/14
Examiner commentary: This is a basic Level 1 response showing some understanding but with significant gaps. The student correctly identifies that gravity causes downward motion and that terminal velocity involves force balance, but the explanations lack detail and precision. Key issues: the terms "weight" and "air resistance force" are not consistently used; Newton's laws are not mentioned or applied; the student says "gravity" rather than "weight force" or "gravitational force"; the explanation of why acceleration decreases in stage 1 is incomplete; there's no explanation of why the second terminal velocity is lower beyond "because the parachute is open." The student also shows a common misconception that at terminal velocity "you stop accelerating" (correct) rather than explicitly stating "acceleration becomes zero" and linking this to force balance via Newton's second law. To improve, this answer needs: explicit reference to Newton's laws; more precise force terminology; quantitative references to the graph; deeper analysis of each stage; and clearer explanation of the cause-and-effect relationships between forces, acceleration, and velocity. The student demonstrates basic conceptual understanding but needs to develop more sophisticated analytical and explanatory skills.