Final answer:
The range of possible speeds for a car speedometer with a 5% uncertainty reading 90 km/h is 85.5 km/h to 94.5 km/h. This converts to a range of 53.1 mi/h to 58.7 mi/h in miles per hour.
Step-by-step explanation:
When a car speedometer has a 5% uncertainty and it reads 90 km/h, we need to calculate the range of possible speeds around this measurement. To find the range, we can calculate 5% of 90 km/h, which is 4.5 km/h.
Therefore, the speedometer could be showing a speed that is 4.5 km/h less or more than the actual speed.
The range of possible speeds is from 85.5 km/h (90 - 4.5 km/h) to 94.5 km/h (90 + 4.5 km/h).
To convert this range to miles per hour, we use the conversion factor where 1 km = 0.6214 mi.
Multiplying each value in the range by 0.6214 gives us approximately 53.1 mi/h to 58.7 mi/h.