IB Physics HL A.3.4 Work by Constant Force Question Bank

Practise HL work calculations using changing-force graphs, angled forces, braking scenarios and the work–energy relationship in exam questions.

Exam points

Use the area under a changing-force graph to calculate work, then apply the work–energy relationship.
Resolve a force along displacement and calculate work for angled pulls, braking forces and energy transfer.

[Maximum number: 2]

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.3.4—Work by constant force question 1 — IB Physics HL

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

Euan drags his foot along the ground to act as a brake. The merry-go-round comes to a stop after 4.0 rotations. The radius of the merry-go-round is 1.5 m . The average frictional force between his foot and the ground is 45 N . Calculate the work done.

distance travelled by Euan $=4.0 \times 2 \pi \times 1.5(=37.70 \mathrm{~m})$ ;

W\left(=F_{a v} d=45 \times 37.70\right)=1700(\mathrm{~J}) ;

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A.3.4—Work by constant force question 1