Explanation:

- The force of gravity acting on an object is calculated using the formula \( F = mg \), where \( m \) is mass in kilograms and \( g \) is the acceleration due to gravity.

- On Earth, the average acceleration due to gravity is approximately \( g = 9.8 \, \text{m/s}^2 \).

- This means the force of gravity on 1 kg is about 9.8 N, simplified as around 10 N.

- Option 1: 20 N - This is approximately double the actual force.

- Option 2: 10 N - This is correct as it closely approximates 9.8 N.

- Option 3: 5 N - This is about half of the force experienced.

- Option 4: 15 N - This is higher than the actual value but closer than option 1 or 3.