Physics Rotational & Circular Motion ETEA 2010
PMDC Verified Question 93 of 95
When a body moves in a circle the angle between its linear velocity and angular velocity is always:
A
\( 0^\circ \)
B
\( 180^\circ \)
C
\( 360^\circ \)
D
\( 90^\circ \)
Tap any option to test your recall and reveal the step-by-step Propolis autopsy.

Propolis Cognitive Error Autopsy

Official Correct Choice:
Option D: \( 90^\circ \)
Concept:

In uniform circular motion, the linear velocity vector lies tangent to the circular path, while the angular velocity vector points along the axis of rotation.

Formula:

$$ \vec{v} = \vec{\omega} \times \vec{r} $$

Solution:

  • By the right-hand rule, \( \vec{\omega} \) is perpendicular to the entire plane of motion.
  • Since \( \vec{v} \) is strictly in the plane of motion, the angle between the plane and its normal axis is exactly \( 90^\circ \).


Why other options are incorrect:

  • Option A and Option B imply they are parallel or anti-parallel, which violates the cross-product vector definition.
  • Option C is geometrically equivalent to \( 0^\circ \).

Quality & Fidelity Assurance: Every question on BeambePrep is rigorously curated against the official PMDC syllabus with zero filler, zero out-of-syllabus content, and zero typos. When an authentic past paper originally contained a historical mistake or ambiguity from the examining board (such as UHS or NUMS), BeambePrep faithfully reflects the original paper while detailing the nuance and scientific consensus in the autopsy above.

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