Lee and Leigh are twins. At their first birthday party, Lee is placed on a spaceship that travels away from the earth and back at a steady 0

Question

Lee and Leigh are twins. At their first birthday party, Lee is placed on a spaceship that travels away from the earth and back at a steady 0.714 c . The spaceship eventually returns, landing in the swimming pool at Leigh’s eleventh birthday party. When Lee emerges from the ship, how old is he?

a. He is still only 1 year old
b. He is 8 years old
c. He is also 11 years old
d. He is 18 years old

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Sapo 5 years 2021-08-29T23:51:29+00:00 1 Answers 12 views 0

Answers ( )

  1. minhkhang
    0
    2021-08-29T23:52:49+00:00
    Reply

    Answer:

    b. He is 8 years old

    Explanation:

    We will use Einstein’s formula for time dilation, to calculate the age of Lee. Because Lee was traveling comparable to the speed of light, his age must be lesser than Leigh.

    T = \frac{T_o}{\sqrt{1-\frac{v^2}{c^2} } }

    where,

    T₀ = Time on Earth = ?

    T = Relative Time = 10 years

    v = relativistic speed of Lee = 0.714 c

    c = speed of light = 3 x 10⁸ m/s

    Therefore,

    10\ years = \frac{T_o}{\sqrt{1-\frac{(0.714\ c)^2}{c^2} } } \\\\

    T₀ = 7 years

    Hence, the age of Lee will be:

    Lee's\ Age = 1\ year + 7\ years = 8\ years

    b. He is 8 years old

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