I timed the big wheel as it went round. 42 seconds for a complete spin. 2 pi radians in 42 seconds is 0.15 radians per second - the angular velocity. Linear velocity v = radius x angular velocity. I estimate the radius to be 15 metres. So the people are moving at a speed v of 2.2 metres per second along a tangent to the circle. They have an angular acceleration towards the centre which is v squared/r = 0.33 m/s/s.
