Answer
$11.9\ rad/s$
Work Step by Step
From the kinematic equations, time taken by the toast to fall is:
$t=\sqrt \frac{2s}{g}$
$t=\sqrt \frac{2\times 0.76\ m}{9.8\ m/s^2}$
$t=0.394\ s$
For maximum angular speed, the toast rotates at $\frac{3}{4}$ of a revolution.
The formula for angular speed is $\omega=\frac{Δθ( rev)}{ΔT(sec)}$
Therefore;
$ω_{max}=\frac{0.75\ rev}{0.394\ s}$
Since $1\ rev=2π\ rad$;
$ω_{max}=\frac{0.75\times 2\pi }{0.394\ s}=11.9\ rad/s$
