Answer
a. 6.0 mV.
b. 0.813V.
The Earth’s field is small and the motional emfs are not important in these situations.
Work Step by Step
a.
$$\epsilon = vBL=(80.47m/s)(0.50\times10^{-4}T)(1.5m)=6.0\times10^{-3}V$$
This is rather small, and not very noticeable.
b.
$$\epsilon = vBL=(252.58m/s)(0.50\times10^{-4}T)(64.4m)=0.813V$$
This is rather small, and not very noticeable.