Okay just imagine two circles. There is a point at the bottom of each circle where the circle touches a piece of paper.
A line is drawn where that point is across the sheet as each circle makes one full rotation in 1 minutes time.
Obviously, the line on the larger circle will be larger than the line on the smaller circle, even though they made the same rotation, so even though they have the same numbers of revolutions per minute, the larger circle is moving faster, so it’s velocity is faster at the same ratio as the diameter of the two circles.
Maybe the dad doesn’t fully understand it himself and has just accepted it as a fun little physics fact.
I’m losing confidence that I understand it
Okay just imagine two circles. There is a point at the bottom of each circle where the circle touches a piece of paper.
A line is drawn where that point is across the sheet as each circle makes one full rotation in 1 minutes time.
Obviously, the line on the larger circle will be larger than the line on the smaller circle, even though they made the same rotation, so even though they have the same numbers of revolutions per minute, the larger circle is moving faster, so it’s velocity is faster at the same ratio as the diameter of the two circles.