Question

Your car’s speedometer is geared to accurately give your speed using a certain tire size: 15” diameter wheels (the metal part) and 4.7” tires (the rubber part).

(a)   If your car's instruments are properly calibrated, how many times should your tire rotate per second if you are travelling at 40 mi/hr?
rotations =

report answer accurate to 3 decimal places.

(b)   You buy new 5.35” tires and drive at a constant speed of 60 mph (according to your car’s instrument). However, a cop stops you and claims that you were speeding. How fast did the radar gun clock you moving?
actual speed =  mph
Report answer accurate to the nearest whole number.

(c)   Then you replace your tires with 4.05” tires. When your speedometer reads 35 mph, how fast are you really moving?
actual speed = mph
Report answer accurate to 1 decimal places

Answer 1