The kinetic energy of a moving object is E=12mv2. A 61 kg runner is moving at 10kmh. However, her speedometer is only accurate to within 0.1kmh. What is the potential error in her calculated kinetic energy, as a result of the imprecision in the measurement of her velocity?

Respuesta :

Answer:

[tex]e=3367.2J[/tex]

%[tex]e=1.43[/tex]%

Explanation:

From the exercise we know two information. The real speed and the experimental measured by the speedometer

[tex]v_{r}=10km/h=2.77m/s[/tex]

Since the speedometer is only accurate to within 0.1km/h the experimental speed is

[tex]v_{e}=10km/h-0.1km/h=9.9km/h=2.75m/s[/tex]

Knowing that we can calculate Kinetic energy for the real and experimental speed

[tex]E_{r}=\frac{1}{2}mv^2=\frac{1}{2}(61000g)(2.77m/s)^2=234023J[/tex]

[tex]E_{e}=\frac{1}{2}mv^2=\frac{1}{2}(61000g)(2.75m/s)^2=230656J[/tex]

Now, the potential error in her calculated kinetic energy is:

[tex]e=E_{r}-E_{e}=(234023-230656)J=3367.2J[/tex]

%[tex]e=\frac{E_{r}-E_{e}}{E_{r}}x100=\frac{(234023-230656)J}{234023J}x100=1.43[/tex]%

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