(1) Angular speed=5.6/0.4=14 radians/sec, where 0.4m is the radius of the wheel.
Since 2π radians is one revolution, 14 radians/s is 14/2π=2.23 revs/s or 133.7 rpm.
(2) We have to add the tangential speed to the translational speed. The direction is important so we should consider velocity rather than the speed because the tangential velocity is changing but the translational velocity stays the same. At 0.80m the blue dot is at its highest point and the tangential velocity is in the direction of motion=14×0.4=5.6m/s. So the speed of the blue dot is 5.6+5.6=11.2m/s.
(3) The blue dot is 0.4m above the road in two different places. The tangential velocity is vertically upwards or vertically downwards, for the trailing or leading edge of the wheel respectively. The resultant velocity is at an angle of 45° to the road and has a magnitude (speed) of 5.6√2=7.92m/s. This magnitude applies equally to both endpoints of the horizontal diameter. The direction for each velocity is different.