Answer
The distance the spot has moved is $59.3m$
Work Step by Step
The number of revolutions the disk rotates in $45s$ is $1.4\times45=63rev$
Since the disk's radius is $15cm$ or $0.15m$, 1 revolution of the disk corresponds to $0.15m\times2\pi=0.942m$
So the distance the spot moves for 63 revolutions is $0.94m\times63=59.3m$
