$\Delta x . \Delta p=\frac{h}{4 \pi}$

$\Delta x=\Delta p(\Delta x=$ uncertainty in position)

$(\Delta p)^{2}=\frac{h}{4 \pi} \quad(\Delta p=m \times \Delta v)$

$m^{2} \Delta v^{2}=\frac{h}{4 \pi} \quad m=m a s s$

$\Delta v^{2}=\frac{h}{m^{2} 4 \pi}$

$\Delta v=\frac{1}{2 m} \sqrt{\frac{h}{\pi}}$

$\Delta v=$ uncertinty in velocity)