Physics - Rotation Question with Solution | TestHub

PhysicsRotationRotational KinematicsEasy2 minPYQ_2020

PhysicsEasysingle choice

When a ceiling fan is switched off, its angular velocity reduces to $50 %$ while it makes $36$ rotations. How many more rotations will it make before coming to rest? (Assume uniform angular retardation)

Options:

Answer:

Solution:

${(\frac{ω_{0}}{2})}^{2} = ω_{0}^{2} - 2 α θ_{1} \Rightarrow 2 α θ_{1} = \frac{3}{4} ω_{0}^{2}$ ....(i)

$0 = {(\frac{ω_{0}}{2})}^{2} - 2 α θ_{2} \Rightarrow 2 α θ_{2} = \frac{ω_{0}^{2}}{4}$ ...(ii)

From (i) & (ii) $\frac{θ_{1}}{θ_{2}} = 3$

$\Rightarrow θ_{2} = \frac{θ_{1}}{3} = \frac{36}{3} = 12$ rotations

Stream:NTA_ABHYAS_NEETSubject:PhysicsTopic:RotationSubtopic:Rotational Kinematics

⏱ 2mℹ️ Source: PYQ_2020

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