AQA GCSE Physics Physics Paper 2 (Foundation), June 2023: Question 10

✅ Correct Answer

• Length: 7.1 cm (Acceptable range: 7.0 cm to 7.3 cm)
• Displacement: 497 m (Calculated as 7.1 × 70)

💡 Key Knowledge

Displacement is a vector quantity defined as the straight-line distance from the start point to the finish point in a stated direction. Always use a ruler to measure directly between the start and finish dots, ignoring the curved path taken.

📐 Calculation Steps

1. Step 1: Measure the straight-line distance on Figure 25 using a ruler in cm. (e.g., 7.1 cm)
2. Step 2: Multiply your measured length by the scale factor given ( 70 m per cm).
3. Step 3: 7.1 cm × 70 m/cm = 497 m .

❌ Common Errors

Students often try to measure the curved route using string or by breaking it into sections. Remember: displacement only cares about the direct straight-line distance, not the total distance travelled!

✅ Correct Answer

• Resultant horizontal force = 0 N

💡 Key Knowledge

To find the resultant force, combine forces acting in opposite directions. Forces pointing left are negative, and forces pointing right are positive.

📐 Calculation Steps

1. Sum of forces to the right (Thrust) = 14,000 N
2. Sum of forces to the left (Friction + Air resistance) = 9,500 N + 4,500 N = 14,000 N
3. Resultant force = 14,000 N - 14,000 N = 0 N

🧠 Exam Technique

Always double-check if there are multiple opposing forces on one side. Here, you had to add friction and air resistance together before subtracting them from the forward thrust.

✅ Correct Answer

• Constant velocity (or constant speed in a straight line)

💡 Key Knowledge

Newton's First Law states that if the resultant force acting on an object is zero ( 0 N ), the object will remain at rest or continue to move at a constant velocity in a straight line.

❌ Common Errors

Do not write "stationary". Because the aeroplane was already moving, zero resultant force means it keeps moving at a steady speed, it does not suddenly stop.

✅ Correct Answer

• Any one from: tension, normal contact force (or normal reaction), or upthrust.

💡 Key Knowledge

A contact force requires two objects to be physically touching to exert a force on each other. Examples include friction, air resistance, tension, normal contact force, and upthrust.

❌ Common Errors

Do not list non-contact forces like gravity (weight), electrostatic force, or magnetic force. Also, avoid writing "drag" if air resistance is already stated in the stem.

✅ Correct Answer

• A horizontal line along the x-axis (or constant low velocity) from 0 to 10 s .
• A straight line with a positive gradient (sloping upwards) starting from 10 s .

💡 Key Knowledge

Converting graphs requires translating features:

• A flat, horizontal section on a distance-time graph (stopped) becomes zero velocity on a v-t graph.
• An increasing gradient (accelerating) on a distance-time graph becomes an upward sloping line (constant acceleration) on a velocity-time graph.

🧠 Exam Technique

Pay close attention to the time axis values. The transition from stationary to accelerating happens precisely at 10 seconds as shown in Figure 27.

✅ Correct Answer

• Atmospheric pressure = 28 kPa (Acceptable range: 26 to 32 kPa, depending on your line of best fit).

💡 Key Knowledge

Extrapolation means extending a line of best fit beyond the plotted data points to estimate values outside the measured range.

📐 Working Out

1. Carefully draw a smooth curve or line of best fit passing through the plotted points on Figure 29.
2. Continue the line smoothly up to a height of 10 km on the x-axis.
3. Read across to the y-axis to find the corresponding pressure value.

❌ Common Errors

Do not connect the dots with straight dot-to-dot lines unless instructed; a smooth line of best fit is required for curved relationships.

✅ Correct Answer

• The average density of the air above the aeroplane decreases. (Tick the first box)

💡 Key Knowledge

As altitude (height above ground) increases, the number of air molecules per unit volume decreases. This means the atmosphere becomes less dense, which is why atmospheric pressure also drops as you go higher.

🧠 Exam Technique

Read all four options carefully before ticking. Ensure you only place a single tick in the correct box to avoid losing the mark.