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MYP Physics · 03 · data analysis

Finding cart mass from force data

Forces · Original GioPhysics question with a detailed, mark-by-mark answer guide.

Demand
demanding
Marks
8
Topics
2
Answer
Complete
data analysis8 marks

A cart is pulled along a horizontal track. The same resistive force acts in every run.

Applied force and measured acceleration
Applied force / NAcceleration / m s⁻²
1.00.20
2.00.60
3.01.00
4.01.40
5.01.80
  1. a

    Determine Use the change across the data to determine the cart's mass. Show how the units support your answer.

    3 marks
  2. b

    Calculate Use one data row to calculate the resistive force.

    3 marks
  3. c

    Explain Explain why a graph of applied force against acceleration would not pass through the origin.

    2 marks
Ready to self-mark?Reveal the detailed answer guide
Answer overviewKey answer: Finds slope ΔF ÷ Δa = (5.0 − 1.0) ÷ (1.80 − 0.20). Obtains mass = 2.5 kg from F = ma. Recognises N per m s⁻² is equivalent to kg.
01

a

3 marks

Determine Use the change across the data to determine the cart's mass. Show how the units support your answer.

How to approach it

Read the data before explaining it. Quote the relevant values or trend, show the comparison or calculation, and then connect that numerical evidence to the physical conclusion—including uncertainty or anomalies when they matter.

  1. 1

    Finds slope ΔF ÷ Δa = (5.0 − 1.0) ÷ (1.80 − 0.20).

  2. 2

    Obtains mass = 2.5 kg from F = ma.

  3. 3

    Recognises N per m s⁻² is equivalent to kg.

02

b

3 marks

Calculate Use one data row to calculate the resistive force.

How to approach it

Read the data before explaining it. Quote the relevant values or trend, show the comparison or calculation, and then connect that numerical evidence to the physical conclusion—including uncertainty or anomalies when they matter.

  1. 1

    Uses applied force − resistive force = ma.

  2. 2

    For example, at 3.0 N calculates ma = 2.5 × 1.00 = 2.5 N.

  3. 3

    Obtains resistive force = 0.50 N, opposing the motion.

03

c

2 marks

Explain Explain why a graph of applied force against acceleration would not pass through the origin.

How to approach it

Read the data before explaining it. Quote the relevant values or trend, show the comparison or calculation, and then connect that numerical evidence to the physical conclusion—including uncertainty or anomalies when they matter.

  1. 1

    The applied force must first balance the approximately constant resistive force.

  2. 2

    Therefore zero acceleration occurs at a non-zero applied force of about 0.50 N.

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