Answer
The difference between the angular speeds of the wheels is $1.47rad/s$
Work Step by Step
Since 2 wheels have different $\omega$, the rotation circle of each wheel is different from each other. The distance between the left and right tires is $1.6m$, so if the radius of the rotation circle of the wheels on one side is $R$, that of the wheels on the other side is $R+1.6m$
The perimeter of each circle is $2\pi R$ and $2\pi (R+1.6)$
$t$ is the time finished to finish 1 lap. The linear velocity of each wheel, then, is $$v_1=\frac{2\pi R}{t}$$ $$v_2=\frac{2\pi(R+1.6)}{t}$$
Therefore, $$\omega_1-\omega_2=\frac{v_1}{r_{wheel}}-\frac{v_2}{r_{wheel}}=\frac{2\pi R}{rt}-\frac{2\pi(R+1.6)}{rt}$$ $$\omega_1-\omega_2=\frac{2\pi R}{rt}-\frac{2\pi R}{rt}-\frac{2\pi\times1.6}{rt}=-\frac{3.2\pi}{rt}$$
We know $t=19.5s$ and $r_{wheel}=0.35m$. Therefore, $$\omega_1-\omega_2=-1.47rad/s$$
So the difference between the angular speeds of the wheels is $1.47rad/s$
