The centripetal force \( F_{\text{c}} \) for an object in circular motion is calculated using the formula:
\[
F_{\text{c}} = \frac{mv^2}{r}
\]
Given the following values:
- Mass (\( m \)) = \( 800 \, \text{kg} \)
- Speed (\( v \)) = \( 20 \, \text{m/s} \)
- Radius (\( r \)) = \( 50 \, \text{m} \)
Substituting these values into the formula:
\[
F_{\text{c}} = \frac{800 \times (20)^2}{50} = \frac{800 \times 400}{50} = 6400 \, \text{N}
\]
The centripetal force acting on the car is \( 6400 \, \text{N} \).