#### (a) A car speedometer has a 5.0% uncertainty. What is the range of possible speeds when it reads 90km/h?

(b) Convert this range to miles per hour. (1km=0.6214 mi)

**SOLUTIONS:**

a) The uncertainty in the velocity of the car is computed as

Therefore, the range of the possible speeds is

So the range of the possible speeds is 85.5 km/hr to 94.5 km/hr

b) Convert the range to mi/h

For 85.5 km/hr

For 94.5 km/hr

Therefore, the range can be represented as 53.13 mi/hr to 58.72 mi/hr.