The force of attraction between two masses due to gravity can be calculated using Newton's law of universal gravitation:\( F = G \frac{m_1 m_2}{r^2} \)

where:

• \( F \) is the force of attraction between the masses,
• \( G \) is the gravitational constant,
• \( m_1 \) and \( m_2 \) are the two masses, and
• \( r \) is the distance between the centres of the two masses.

Given that \( G = 7 \times 10^{-11} \, \text{Nm}^2\text{kg}^{-2} \), \( m_1 = 10^6 \, \text{kg} \), \( m_2 = 10^3 \, \text{kg} \), and \( r = 1 \, \text{m} \), we can substitute these values into the formula:

\( F = 7 \times 10^{-11} \frac{10^6 \times 10^3}{1^2} = 7 \times 10^{-2} \, \text{N} \)

So, the force of attraction between the 10⁶kg mass of lead and the 10³kg mass of iron is 7x10^-2N