New Zealand examsNCEA Level 2

NCEA 91171: mechanics (Level 2 Physics)

Published 12 Nov 20267 min read

NCEA Level 2 Physics

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What NCEA 91171 assesses

NZQA says assessment is limited to a selection from the topics in the standard (version 2):

Motion: constant acceleration in a straight line, free fall, projectile motion, and circular motion at constant speed with one force providing the centripetal force
Force: force components, vector addition of forces, unbalanced force and acceleration, equilibrium (balanced forces and torques), centripetal force, and force and extension of a spring
Momentum and energy: momentum, change in momentum and impulse, impulse and force, conservation of momentum in one dimension, work, power and conservation of energy, and elastic potential energy

The three grades are about how you write, not just what you know. Achieved means writing statements that show an awareness of how simple facets of phenomena, concepts or principles relate to a described situation. Merit (in-depth understanding) means writing statements that give reasons why they relate, and for mathematical solutions the information may not be directly usable or immediately obvious. Excellence (comprehensive understanding) means writing statements that show the connections between concepts.

The NCEA 91171 exam in 2026 and 2027

NCEA 91171 is one of three Level 2 Physics externals, with 91170 (waves) and 91173 (electricity and electromagnetism). The 2026 exam is on Wednesday 18 November, in the afternoon session. NZQA's specifications for both years say the exam is on printed paper and 91171 is a 6-credit external. In 2025 its three questions covered acceleration, momentum, and energy with circular motion and torque.

Equipment: an approved calculator, a ruler and a protractor. Scientific or graphing calculators are both fine.
Resource sheet: the formulae and the values of physical constants you need come in a separate resource sheet with the exam papers. The acceleration due to gravity is given as g = 9.8 m s⁻².
Show your reasoning: use numerical working, words and diagrams. Mathematical solutions must show mathematically how two phenomena, concepts or principles are connected.
Units and figures: give an appropriate unit, keep the number of significant figures consistent with the data in the question, and know the prefixes micro, milli, centi, kilo and mega.

How NCEA 91171 is marked

Three questions, each scored N0 to E8, give a total out of 24. In 2025 they covered acceleration, momentum, and energy with circular motion and torque. Because physics marks are earned by evidence such as a correct equation, a substitution or an explained step, partial working can still earn units.

NCEA 91171 cut scores

Mechanics boundaries have been steady since 2022 at 8, 14 and 19. Only 2021 differed, with Excellence at 20. Each score below is where the grade begins, out of 24.

Year	Achieved from	Merit from	Excellence from
2025	8	14	19
2024	8	14	19
2023	8	14	19
2022	8	14	19
2021	8	14	20

Cut scores 2025

2025 schedule: Achieved from 8, Merit from 14, Excellence from 19. The same as 2024.

Cut scores 2024

2024 schedule: Achieved from 8, Merit from 14, Excellence from 19. The same as 2023.

Cut scores 2023

2023 schedule: Achieved from 8, Merit from 14, Excellence from 19. The same as 2022.

Cut scores 2022

2022 schedule: Achieved from 8, Merit from 14, Excellence from 19. Compared with 2021, Excellence came down by 1.

Cut scores 2021

2021 schedule: Achieved from 8, Merit from 14, Excellence from 20.

Worked examples at each grade

Achieved: constant acceleration

A cyclist at 2.0 m s⁻¹ accelerates at 0.50 m s⁻² over 60 m. Find the final speed and the time taken. The unknown is v, and you know u, a and s, so:

v^2=u^2+2as=2.0^2+2\times0.50\times60=64\quad\text{so}\quad v=8.0\ \text{m s}^{-1}

t=\frac{v-u}{a}=\frac{8.0-2.0}{0.50}=12\ \text{s}

Check both in the SUVAT Calculator.

Merit: projectile motion

A ball is kicked from the ground at 18 m s⁻¹ at 40° above the horizontal. Find the time in the air and the horizontal range, taking g = 9.8 m s⁻² and ignoring air resistance. Split the velocity into components first:

v_x=18\cos40^\circ=13.8\ \text{m s}^{-1},\quad v_y=18\sin40^\circ=11.6\ \text{m s}^{-1}

t=\frac{2v_y}{g}=\frac{2\times11.57}{9.8}=2.36\ \text{s},\quad\text{range}=v_xt=13.79\times2.361=32.6\ \text{m}

Merit wants the vertical and horizontal motion treated separately and linked by the time. Keep the unrounded components in the calculation, as in the Projectile Motion simulator, which shows the same range.

Excellence: momentum and energy together

A 0.50 kg trolley moving at 3.0 m s⁻¹ hits a stationary 1.5 kg trolley, and they stick together. Find their speed, then compare the kinetic energy before and after.

p_{\text{before}}=0.50\times3.0=1.5\ \text{kg m s}^{-1}\quad\text{so}\quad v=\frac{1.5}{0.50+1.5}=0.75\ \text{m s}^{-1}

E_k\ \text{before}=\frac12\times0.50\times3.0^2=2.25\ \text{J},\quad E_k\ \text{after}=\frac12\times2.0\times0.75^2=0.5625\ \text{J}

Momentum is conserved because no outside force acts, but 1.69 J of kinetic energy has gone. Total energy is still conserved: the missing kinetic energy became thermal energy and sound, and deformation of the trolleys. Excellence asks you to connect the two ideas and say why kinetic energy alone is not conserved in this collision. Check the 0.5625 J in the Kinetic Energy Calculator.

Now try some projectile problems in our Laws of Motion course, then press Mark to check your answer in the course:

Press Mark to have your answer marked in the Laws of Motion course.

Exam answers

The answers and a worked mark scheme come with today's paper once it is marked. We do not publish official or past paper answers. Every question on the daily paper is our own.

Use the daily paper as a practice exam

The Level 2 Physics track above is a short timed mock of 8 questions, not a full exam and not written by NZQA (NCEA Level 2 Physics). It covers kinematics and projectiles, forces, moments and equilibrium, momentum and collisions, and work, energy and power, which is most of 91171. It has no circular motion topic, and it also includes waves, particle physics, the photoelectric effect and materials, which are not part of 91171, so treat those as extra.

Is NCEA 91171 changing?

The 2027 specification for Level 2 Physics keeps 91171 exactly as it is. Looking further ahead, Year 12 moves to the NZ Certificate of Education in 2029.

Common mistakes in NCEA 91171

Confusing momentum and impulse. NZQA's 2025 report says some Merit candidates did, and that some did not treat momentum as a vector.
Mixing up velocity, force and motion in projectiles. The report says candidates found it hard to link them consistently.
No explanation in context. To gain full credit, explain how the physics concept applies to the situation in the question.
Careless data and units. Copy numbers carefully, round sensibly and give a unit with the final answer.
Reusing old answers. The report says candidates who reproduced answers from earlier exams without applying them to this year's context could not show their understanding.
Running calculations without brackets. The report says this often cost higher grades.

Common questions

How many credits is 91171?

Six, the largest Level 2 physics standard along with 91173.

What were the 2025 cut scores?

Achieved 8, Merit 14, Excellence 19, out of 24.

Is g given?

Yes. NZQA says g is given as 9.8 m s⁻², and formulae and constants come in a separate resource sheet.

Do I need a protractor?

Yes. NZQA lists an approved calculator, a ruler and a protractor as required equipment for Level 2 Physics.

Is circular motion included?

Yes, at constant speed with one force providing the centripetal force.

Revision cards

Flip each card to check the answer.

Where to go next

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