IB Physics HL A.2.26 Angular and Linear Speed Question Bank

Practise analysing angular and linear speed in HL circular-motion questions, including orbital periods, rotating bodies and force or torque effects.

Exam points

Derive period, angular speed and tangential speed from orbital data, then check units and significant figures.
Relate force direction and torque to changing linear or angular speed in rotating-body scenarios.
Compare speeds at different radii and justify ratios using v = ωr and uniform circular-motion models.

[Maximum number: 3]

Aibhe and Euan are sitting on opposite sides of a merry-go-round, which is rotating at constant speed around a fixed centre. The diagram below shows the view from above.

Figure for Question A.2.26—Angular and linear speed question 1 — IB Physics HL

Aibhe is moving at speed $1.0 \mathrm{~m} \mathrm{~s}^{-1}$ relative to the ground.

Aibhe moves so that she is sitting at a distance of 0.75 m from the centre of the merry-go-round, as shown below.

Euan pushes the merry-go-round so that he is again moving at $1.0 \mathrm{~ms}^{-1}$ relative to the ground.

Determine Aibhe's speed relative to the ground.

Aibhe's period of revolution is the same as before;
from $v=\frac{2 \pi r}{T}$ , since r is halved, v is halved;
$v=0.5\left(\mathrm{~ms}^{-1}\right) ;$

Marking guidance:

Award [3] for a bald correct answer.

All question bank results loaded

A.2.26—Angular and linear speed question 1