Question

Question
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 520 kilograms. How much kinetic energy do they have?
KE=1/2mv^2


(1 point)
Responses

451,584.0 J
451,584.0 J

90,480.6 J
90,480.6 J

458,640 J
458,640 J

91,894.4 J
91,894.4 J
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Answer 1

To calculate the kinetic energy (KE) of the racehorse and its jockey, we 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:
- \( m = 520 \) kg,
- \( v = 18.8 \) m/s.

Plugging in the values:

\[ KE = \frac{1}{2} \times 520 \, \text{kg} \times (18.8 \, \text{m/s})^2 \]

Calculating \( (18.8)^2 \):

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

Now substitute this back into the equation for kinetic energy:

\[ KE = \frac{1}{2} \times 520 \times 353.44 \]

Calculating:

\[ KE = 260 \times 353.44 = 91894.4 \, \text{J} \]

Thus, the kinetic energy of the racehorse and its jockey is **91,894.4 J**.

The correct response is:

**91,894.4 J**