A racehorse is running at 42 miles per hour, equivalent to 18.8 meters per second. The horse and its jockey have a combined mass of 512 kilograms. How much kinetic energy do they have? KE=12mv2 (1 point) Responses 451,584.0 J 451,584.0 J 90,480.6 J 90,480.6 J 180.961.3 J 180.961.3 J 4,812.8 J

1 answer

The kinetic energy (KE) can be calculated using the formula:

\[ KE = \frac{1}{2} m v^2 \]

where:

  • \( m \) is the mass in kilograms,
  • \( v \) is the velocity in meters per second.

Given:

  • \( m = 512 \) kg (mass of the horse and jockey),
  • \( v = 18.8 \) m/s (velocity of the horse).

Now, we can substitute the values into the formula:

\[ KE = \frac{1}{2} \times 512 , \text{kg} \times (18.8 , \text{m/s})^2 \]

Calculating \( (18.8 , \text{m/s})^2 \):

\[ (18.8)^2 = 353.44 , \text{m}^2/\text{s}^2 \]

Now, plugging it back into the kinetic energy formula:

\[ KE = \frac{1}{2} \times 512 \times 353.44 \]

Calculating:

\[ KE = 256 \times 353.44 = 90,480.64 , \text{J} \]

Rounding this to one decimal place gives:

\[ KE \approx 90,480.6 , \text{J} \]

Thus, the kinetic energy of the horse and its jockey is approximately 90,480.6 J.