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=1/2mv2


(1 point)
Responses

451,584.0 J
451,584.0 J

180.961.3 J
180.961.3 J

90,480.6 J
90,480.6 J

4,812.8 J

1 answer

To calculate the kinetic energy (KE) of the racehorse and its jockey, you can use the formula:

\[ KE = \frac{1}{2} mv^2 \]

Where:

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

Given:

  • Mass \( m = 512 \) kg
  • Velocity \( v = 18.8 \) m/s

Now, substituting the values into the formula:

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

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

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

Now, substitute this back into the kinetic energy equation:

\[ KE = \frac{1}{2} \times 512 , \text{kg} \times 353.44 , \text{m}^2/\text{s}^2 \] \[ KE = 256 , \text{kg} \times 353.44 , \text{m}^2/\text{s}^2 \] \[ KE = 90,480.64 , \text{J} \]

Rounding this, the kinetic energy is approximately:

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

Thus, the correct answer is:

90,480.6 J