    Question

# The speed of a particle travelling in a circle of radius 20 cm increases uniformly from 6 m/s to 8 m/s in 4 sec. The angular acceleration of particle is :

A
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B
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C
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D
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Solution

## The correct option is C 2.5 rad/ s2Since speed increases uniformly, average tangential acceleration will be equal to instantaneous tangential acceleration. Therefore, instantaneous tangential acceleration is given by, at=dvdt=v2−v1t2−t1 ⇒at=8−64=0.5 m/s2 Angular acceleration of the particle will be, α=atr ⇒α=0.5 m/s2(20100 m) ∴α=52=2.5 rad/s2 Alternatve: α=ωt−ωot=v−urt α=8−60.2×4=20.8=2.5 rad/s2 Why this question ? It intends to your understanding of fundamentals of average and instantaneous tangential acceleration in a circular motion. Tip: In case of uniform circular motion the average and instantaneous value of tangential acceleration will be the same.  Suggest Corrections  0      Similar questions  Explore more