Question

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

• A. $ 45\,ms^{-2} $
• B. $ 182\,ms^{-2} $
• C. $ 187\,ms^{-2} $
• D. $ 192\,ms^{-2} $

Answer 1

The Correct Option is A

Given, angular velocity, $\omega=15\, rad / s$
Time, $t=0.270\, s$
Radius, $r=0.810 \,m$
Acceleration, $a=\frac{v}{t}$
or $a=\frac{r \omega}{t}$
$[\because v=r \omega]$
$a=\frac{0.810 \times 15}{0.270}$
$=45 \,m / s ^{2}$