A car travelling west at 60.0 km/h decelerates at 6.50 m/s. The car's tires have a radius of 0.310 m. Question 1 (a) What is the magnitude of the tires' angular acceleration? (b) How many revolutions do the tires make before coming to rest? A car travelling west at 60.0 km/h decelerates at 6.50 m/s. The car's tires have a radius of 0.310 m. Question 1 (a) What is the magnitude of the tires' angular acceleration? (b) How many revolutions do the tires make before coming to rest?