The cyclist travels at a speed of 18 km / h. What is the linear velocity of points on the rim of a wheel if its diameter is 50 cm?

Data: Vв – cyclist’s speed (Vв = 18 km / h = 5 m / s); d – wheel diameter (d = 50 cm = 0.5 m).

1) Linear speed of points on the indicated wheel rim relative to its center: V = Vw = 5 m / s.

2) Linear speed of points on the indicated wheel rim relative to the road:

a) lower point: Vн = 0 m / s.

b) upper point: Vv = 2Vv = 2 * 5 = 10 m / s.

c) points on the horizontal axis passing through the center: Vg = √ (V ^ 2 + Vvr ^ 2) = √ (2V ^ 2) = 5 * √2 m / s.

3) Angular velocity: ω = Vv / R = 2Vv / d = 2 * 5 / 0.5 = 20 rad / s.