Express your answers to problems in this section to the correct number of significant figures and proper units. (a) A car speedometer has a 5.0% uncertainty. What is the range of possible speeds when it reads 90 km/h ? (b) Convert this range to miles per hour. (1 km = 0.6214 mi)

Solution 13 PE: Step 1 of 6 (a) Use following formula to find percentage uncertainty of speed, % uncertainty = v× 100 v v = (% uncertainty)(v) 100 Comment Step 2 of 6 Here is the speed and is the uncertainty in speed. Comment Step 3 of 6 Substitute for and for the percentage uncertainty. Therefore, 5 v = 100× 90km/h = 4.5km/h Therefore, the range of the possible speed in kilometer per hour is . Comment