To find the speed of the horse, we can use the formula that relates momentum (p), mass (m), and speed (v):
\[ p = m \cdot v \]
where:
- \( p \) is the momentum,
- \( m \) is the mass, and
- \( v \) is the speed.
We can rearrange this formula to solve for speed \( v \):
\[ v = \frac{p}{m} \]
Given that the mass \( m \) of the horse is 500 kg and the momentum \( p \) is 8220 kg•m/s, we can substitute these values into the equation:
\[ v = \frac{8220 , \text{kg•m/s}}{500 , \text{kg}} \]
Calculating this:
\[ v = 16.44 , \text{m/s} \]
Thus, the speed of the horse is approximately 16.44 m/s.