Question

Tangential acceleration at = $r\alpha$ = constant = K
$\alpha = \frac{K}{r}$
At the end of second revoluation angular velocity is w then
w² - w₀² = $\propto \theta$
w² - O² = 2$\left(\frac{K}{r}\right)\left(4\pi \right)$
w² = $\frac{8\pi K}{r}$
K.E. of the particle is = K.E.= $\frac{1}{2}$ mv²
K.E. = $\frac{1}{2}$ mv²w²
K.E. = $\frac{1}{2}$ m(r²)$\left(\frac{8\pi K}{r}\right)$
8 $\times$10^-4 = $\frac{1}{2}$ $\times$ 10 $\times$ 10^-3 $\times$ 6.4 $\times$ 10^-2 $\times$ 3.14 $\times$ K
$K=\frac{2}{6.4\times 3.14}=0.1\frac{m}{sse{c}^2}$