(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. (1 km=0.6214 mi)

Answer :

Answer:

a) 90 ± 4.5 km/h

b) 55.926 ± 2.7963 mi/h

Explanation:

The error of 5 % uncertainty would be

[tex]\frac{5}{100}\times 90=4.5[/tex]

Range of possible speeds is 90 ± 4.5 km/h

First convert 90 km/h to mi/h

1 km/h = 0.6214 mi/h

90 km/h = 90×0.6214

⇒90 km/h = 55.926 mi/h

Convert 4.5 km/h to mi/h

4.5 km/h = 4.5×0.6214

⇒4.5 km/h = 2.7963

Range of possible speeds is 55.926 ± 2.7963 mi/h

Answer:

(a). 90±45 km/hr

(b). 55.926 ± 2.7963 mil/hr

Explanation:

Given that,

Uncertainty = 5.0%

[tex]\delta A=\dfrac{5}{100}[/tex]

Here, A = 90 km/h

(a). We need to calculate the range of speed

We need to calculate the error of 5.0% uncertainty

[tex]\delta A=\dfrac{5}{100}\times90[/tex]

Here, [tex]\delta A[/tex] = uncertainty

[tex]\delta A=4.5\ km/h[/tex]

(b). We need to convert this range to miles per hour

1 km = 0.6214 mil

[tex]90\ km/h=90\times0.6214[/tex]

[tex]90\ km/h=55.926\ mil/hr[/tex]

[tex]4.5\ km/h = 4.5\times 0.6214[/tex]

[tex]4.5 km/h=2.7963\ mil/hr[/tex]

Hence, This is the required solution.

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