MYP Physics · 02 · extended response
Choosing a model for a water jet
Motion · Original GioPhysics question with a detailed, mark-by-mark answer guide.
- Demand
- discriminating
- Marks
- 8
- Topics
- 2
- Answer
- Complete
A designer aims a fountain nozzle horizontally from a platform 1.25 m above a pool. Water leaves at 4.0 m s⁻¹. A simple projectile model uses g = 10 m s⁻² and ignores air resistance. The target drain is 2.2 m horizontally from the nozzle.
- a
Determine Determine the modelled time for the water to fall to pool level.
2 marks - b
Predict Predict whether the water reaches the drain and support the prediction quantitatively.
2 marks - c
Evaluate Evaluate how useful this result is for the real fountain and recommend one next design step.
4 marks
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a
Determine Determine the modelled time for the water to fall to pool level.
Build a chain of claim, evidence and physics reasoning. Address more than one relevant factor, identify a limitation or assumption, and finish with a conclusion that is conditional on the evidence rather than absolute.
- 1
Uses 1.25 = ½ × 10 × t².
- 2
Obtains t = 0.50 s.
b
Predict Predict whether the water reaches the drain and support the prediction quantitatively.
Build a chain of claim, evidence and physics reasoning. Address more than one relevant factor, identify a limitation or assumption, and finish with a conclusion that is conditional on the evidence rather than absolute.
- 1
Calculates horizontal distance = 4.0 × 0.50 = 2.0 m.
- 2
Concludes that the model predicts the water lands 0.2 m short of the 2.2 m drain.
c
Evaluate Evaluate how useful this result is for the real fountain and recommend one next design step.
Build a chain of claim, evidence and physics reasoning. Address more than one relevant factor, identify a limitation or assumption, and finish with a conclusion that is conditional on the evidence rather than absolute.
- 1
Identifies a relevant model limitation, such as water breaking into droplets, air drag, or an uncertain exit speed.
- 2
Explains a likely effect of that limitation or uncertainty on the landing position.
- 3
Recognises that a 0.2 m shortfall is large enough that relying on the ideal result alone is risky.
- 4
Recommends a controlled prototype test or adjustable nozzle followed by measured landing positions.
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