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Question

Physics Question on rotational motion

An athlete throws a discus from rest to a final angular velocity of 15rads115\, rad\, s ^{-1} in 0.270s0.270\, s before releasing it. During acceleration, discus moves a circular arc of radius 0.810m0.810 \,m. Acceleration of discus before it is released is

A

45ms245\,ms^{-2}

B

182ms2182\,ms^{-2}

C

187ms2187\,ms^{-2}

D

192ms2192\,ms^{-2}

Answer

45ms245\,ms^{-2}

Explanation

Solution

Given, angular velocity, ω=15rad/s\omega=15\, rad / s
Time, t=0.270st=0.270\, s
Radius, r=0.810mr=0.810 \,m
Acceleration, a=vta=\frac{v}{t}
or a=rωta=\frac{r \omega}{t}
[v=rω][\because v=r \omega]
a=0.810×150.270a=\frac{0.810 \times 15}{0.270}
=45m/s2=45 \,m / s ^{2}