Answer:
7.38 rad/s
Explanation:
Assume no air resistance, we can first calculate the time it takes for the toast to be dropped 0.89m to the floor. Since we have
[tex] h = \frac{gt^2}{2}[/tex]
where [tex]g = 9.81m/s^2[/tex] and h = 0.89 m
[tex] t^2 = \frac{2h}{g} = \frac{2*0.89}{9.81} \approx 0.181[/tex]
[tex] t = \sqrt{0.811} \approx 0.426 s[/tex]
This is also the time for the toast to flip one time at a constant angular speed. The angle it covered would be at [tex]\theta = \pi[/tex] radian.
So the smallest angular speed it needs to hit and topple butter-side down is
[tex]\omega = \frac{\theta}{t} = \frac{\pi}{0.426} \approx 7.38 rad/s[/tex]
