If a person lives on the average 100 years in his rest frame, how long does he live in the earth frame if he spends all his life in a spaceship going at 60% of the speed of light .

Explanation

To solve the problem of how long a person lives in the Earth frame while traveling at 60% of the speed of light, we will use the concept of time dilation from the theory of relativity. Here’s a step-by-step solution:

### Step 1: Identify the given values
- The average lifespan of the person in their rest frame (proper time, \( t_0 \)) is 100 years.
- The speed of the spaceship is 60% of the speed of light (\( v = 0.6c \)).

### Step 2: Write the time dilation formula
The time dilation formula is given by:
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