To find the angular speed of the tires, we need to use the formula:
angular speed = linear speed / radius
First, we need to convert the speed from miles per hour to meters per second, and the tire radius from inches to meters:
55 mph = 24.6 m/s (approximately)
15 inches = 15 x 2.54 cm/inch = 38.1 cm = 0.381 m
Now we can calculate the angular speed:
angular speed = linear speed / radius
angular speed = 24.6 m/s / 0.381 m
angular speed = 64.6 radians/second (approximately)
Therefore, the angular speed of the tires is approximately 64.6 radians/second.