A.3 Work, energy and power questions for IB Physics

213 questions on Work, energy and power, written by Augment in the style of IB exam papers. Six of them are below in full, to answer on paper.

IB Physics
Part of A Space, time and motion
SL and HL

Questions by paper and level

SL and HL questions are for students at either level. HL only questions cover what only HL students study.

Paper	SL and HL	HL only	All
Paper 1A	50	12	62
Paper 1B	8	1	9
Paper 2	77	65	142
Every paper	135	78	213

Counted on 10 November 2026

Questions to try

Written by Augment in the style of IB exams, not past papers. Answer them on paper, then check each one against its markscheme with a free account.

Question 1 · PHY-00038Paper 1A · 1 mark

Two identical stones are thrown with the same speed from the same point at the top of a sea cliff. Stone P is thrown horizontally. Stone Q is thrown at $60 °$ above the horizontal. Air resistance is negligible. Which quantity is the same for both stones?

A
the time taken to reach the sea
B
the horizontal component of velocity on reaching the sea
C
the angle to the horizontal at which the stone reaches the sea
D
the speed with which the stone reaches the sea

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Question 2 · PHY-00287Paper 1B · 10 marks

A student investigates her power output when she runs up a flight of stairs at school. She measures the vertical height $h$ of the flight with a tape measure and her mass $m$ with a digital bathroom scale:

$h = (3.10 \pm 0.02) m$
$m = (58.4 \pm 0.1) kg$

A friend times five runs with a stopwatch that reads to 0.01 s. In each run the student starts from rest at the bottom step.

Run	$t$ / s
1	2.84
2	2.91
3	3.62
4	2.78
5	2.87

In run 3 the student slipped on a step.

(a)(i)
Calculate the mean time for the student to run up the stairs. Give your answer to an appropriate number of decimal places.
2 marks
(a)(ii)
Estimate the absolute uncertainty in the mean time.
1 mark
(b)
Show that the average useful power developed by the student is about 600 W.
2 marks
(c)(i)
Calculate the percentage uncertainty in the power.
2 marks
(c)(ii)
Hence state the power with its absolute uncertainty.
1 mark
(d)
The friend's reaction time causes him to start the stopwatch late but stop it on time in every run. Explain the effect of this on the calculated power.
2 marks

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Question 3 · PHY-00004Paper 2 · 7 marks

A cyclist of total mass 80 kg rides along a straight, level road. The graph shows how her velocity $v$ changes with time $t$ .

Velocity-time graph: velocity rises uniformly from 0 to 16 m/s over 4 s, stays at 16 m/s until 10 s, then falls uniformly to 0 at 14 s. — Velocity–time graph for the cyclist.

(a)
Calculate her acceleration during the first 4.0 s.
2 marks
(b)
Determine the total distance travelled.
2 marks
(c)(i)
Calculate her maximum kinetic energy.
1 mark
(c)(ii)
Calculate the average power with which she gains kinetic energy in the first 4.0 s.
2 marks

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Question 4 · PHY-00042Paper 1A · 1 mark

A pendulum bob is held at X with its string taut and is then released from rest. When the string becomes vertical it catches on a fixed peg P directly below the point of suspension O. Air resistance is negligible.

A pendulum hangs from point O on a ceiling. The bob is held at X, to the left, with the string taut at about 50 degrees to the vertical. A small peg P is directly below O, about halfway down. A dashed arc shows the bob's path from X to its lowest point.

On the other side of the peg, the bob rises

A
to the same height as X.
B
higher than X, because the swinging part of the string is shorter.
C
lower than X, because the peg does work against the motion of the bob.
D
lower than X, because the bob moves through a shorter arc.

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Question 5 · PHY-00288Paper 1B · 11 marks

A group of students investigates a spring-loaded launcher that fires a small plastic ball of mass 15.0 g vertically upwards. The spring is compressed by a distance $x$ and released. The students use a video recording against a vertical scale to find the maximum height $h$ that the ball rises above its release point.

The students predict that all the elastic potential energy stored in the spring is transferred to the gravitational potential energy of the ball at its highest point.

The graph shows the variation of $h$ with $x^{2}$ , with error bars and the line of best fit.

Graph of h in metres against x squared in units of 10^-4 m^2. Five points at x^2 = 1, 4, 9, 16, 25 with h = 0.08, 0.29, 0.69, 1.17, 1.89 m, vertical error bars of 0.05 m and horizontal error bars growing from 0.2 to 1.0. A straight best-fit line passes close to the origin.

(a)
Explain why the students expect the graph of $h$ against $x^{2}$ to be a straight line through the origin.
2 marks
(b)(i)
The compression $x$ is measured with an uncertainty of $\pm 1 mm$ . Calculate the absolute uncertainty in $x^{2}$ when $x = 30 mm$ .
2 marks
(b)(ii)
Outline why the horizontal error bars become longer as $x$ increases.
1 mark
(c)(i)
Determine, using the graph, the spring constant $k$ of the spring.
3 marks
(c)(ii)
State the unit of the gradient of the graph.
1 mark
(d)
The manufacturer states that $k = 250 {N m}^{- 1}$ . Suggest why the value obtained from the graph is smaller than this.
2 marks

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Question 6 · PHY-00211Paper 2 · 11 marks

A basketball player takes a free throw. The ball leaves her hands at a height of 2.10 m above the floor with a speed of $7.2 {m s}^{- 1}$ at an angle of $52^{\circ}$ above the horizontal. The centre of the hoop is 3.05 m above the floor and a horizontal distance of 4.20 m from the point of release. Treat the ball as a point and ignore air resistance.

Side view: the ball is released 2.10 m above the floor at 52 degrees above the horizontal. A hoop 3.05 m above the floor is 4.20 m horizontally from the release point, attached to a backboard.

(a)
Show that the horizontal component of the initial velocity of the ball is about $4.4 {m s}^{- 1}$ .
1 mark
(b)
Calculate the time taken for the ball to travel a horizontal distance of 4.20 m.
1 mark
(c)
Determine whether the ball is moving upwards or downwards when it reaches the hoop.
2 marks
(d)
Calculate the height of the ball above the floor when it has travelled a horizontal distance of 4.20 m.
2 marks
(e)
Calculate the maximum height of the ball above the floor.
2 marks
(f)
Determine, using conservation of energy, the speed of the ball when it reaches the hoop.
2 marks
(g)
In practice air resistance acts on the ball. Outline how the player must change the speed of release, at the same angle, for the ball to reach the hoop.
1 mark

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