OCR M4 2004 January — Question 1 5 marks

Exam BoardOCR
ModuleM4 (Mechanics 4)
Year2004
SessionJanuary
Marks5
PaperDownload PDF ↗
Mark schemeDownload PDF ↗
TopicCircular Motion 1
TypeAngular kinematics – constant angular acceleration/deceleration
DifficultyModerate -0.8 This is a straightforward application of constant angular acceleration equations (rotational analogues of SUVAT). Part (i) uses ω² = ω₀² + 2αθ directly, and part (ii) requires finding when the wheel stops then working backwards one revolution. Both parts are routine calculations with no conceptual challenges beyond recognizing the parallel with linear kinematics.
Spec6.05a Angular velocity: definitions

1 A wheel is rotating about a fixed axis, and is slowing down with constant angular deceleration \(0.3 \mathrm { rad } \mathrm { s } ^ { - 2 }\).
  1. Find the angle the wheel turns through as its angular speed changes from \(8 \mathrm { rad } \mathrm { s } ^ { - 1 }\) to \(5 \mathrm { rad } \mathrm { s } ^ { - 1 }\).
  2. Find the time taken for the wheel to make its final complete revolution before coming to rest.

1 A wheel is rotating about a fixed axis, and is slowing down with constant angular deceleration $0.3 \mathrm { rad } \mathrm { s } ^ { - 2 }$.\\
(i) Find the angle the wheel turns through as its angular speed changes from $8 \mathrm { rad } \mathrm { s } ^ { - 1 }$ to $5 \mathrm { rad } \mathrm { s } ^ { - 1 }$.\\
(ii) Find the time taken for the wheel to make its final complete revolution before coming to rest.

\hfill \mbox{\textit{OCR M4 2004 Q1 [5]}}