A car is moving at a speed of 20 m/s in 4 seconds and the car's tire is 38cm around which is its diameter. How many revolutions did your tires make? Relevant Equations, T=2∏r / v My attempt at a solution: To get the distance travelled=20 m/s (4 sec.) = 80 m 2∏(0.19m)= 1.19 m 80m / 1.19 m = 67.22 Rev 67.22 rev / 4 sec. = 16.805 rev/s ? is this wrong?