An imaginary galaxy is considered to consist of `N` starts each of mass `M` and with each pair of stars at a mutual separation of `R`. If `N=4`, `R~~10^(21)m`, `M=2xx10^(30)kg`, find out the gravitational potential energy of galaxy.

Explanation

To find the gravitational potential energy of the galaxy consisting of \( N \) stars, we can follow these steps:

### Step 1: Understand the formula for gravitational potential energy between two masses
The gravitational potential energy \( U \) between two masses \( m_1 \) and \( m_2 \) separated by a distance \( r \) is given by the formula:
\[ U = -\frac{G m_1 m_2}{r} \]
where \( G \) is the gravitational constant.
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