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The average lifetime of a pi meson in its own frame of reference (i.e., the proper lifetime) is 2.6 10-8 s. (a) If the meson moves with a speed of 0.88c, what is its mean lifetime as measured by an observer on Earth? (b) What is the average distance it travels before decaying, as measured by an observer on Earth? (c) What distance would it travel if time dilation did not occur?

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Final answer:

a) The measured lifetime of the pi meson as observed by an Earth observer is longer than its proper lifetime due to time dilation. b) The average distance the meson travels before decaying can be calculated using the velocity and measured lifetime. c) If time dilation did not occur, the distance the meson would travel can be calculated using the velocity and proper lifetime.

Step-by-step explanation:

a) According to time dilation, the average lifetime of the pi meson as measured by an observer on Earth is longer than its proper lifetime. To calculate it, we use the formula for time dilation: t' = t / γ, where t' is the measured lifetime, t is the proper lifetime, and γ is the Lorentz factor. Given that the proper lifetime is 2.6 × 10-8 s and the speed of the meson is 0.88c, we can calculate γ using the formula γ = 1 / √(1 - v2/c2). After calculating γ, we can substitute it into the time dilation formula to find the measured lifetime on Earth.

b) To calculate the average distance the meson travels before decaying, we use the formula d = v · t', where d is the distance, v is the velocity, and t' is the measured lifetime. We can substitute the values given in part a) to find the distance traveled by the meson.

c) If time dilation did not occur, the distance the meson would travel can be calculated using the formula d = v · t, where d is the distance, v is the velocity, and t is the proper lifetime. By substituting the values given in part a) into this formula, we can find the distance the meson would travel in the absence of time dilation.

User George Aristy
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5 votes

Answer:


5.47399* 10^(-8)\ s

14.4513336 m

6.864 m

Step-by-step explanation:

c = Speed of light =
3* 10^8\ m/s

v = Velocity of object =
2.6* 10^(-8)\ m/s

Time dilation is given by


\Delta t'=\frac{\Delta t}{\sqrt{1-(v^2)/(c^2)}}\\\Rightarrow \Delta t'=\frac{2.6* 10^(-8)}{\sqrt{1-(0.88^2c^2)/(c^2)}}\\\Rightarrow \Delta t'=5.47399* 10^(-8)\ s

The mean lifetime as measured by an observer on Earth is
5.47399* 10^(-8)\ s

For an observer on Earth the distance would be


d=0.88* 3* 10^8* 5.47399* 10^(-8)\\\Rightarrow d=14.4513336\ m

The distance traveled is 14.4513336 m

Without time dilation


d=0.88* 3* 10^8* 2.6* 10^(-8)\\\Rightarrow d=6.864\ m

The distance traveled would be 6.864 m

User Funtik
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