A student rides her bicycle down a hill. Together, she and the bicycle have a mass of 56 kilograms. She is moving at 11 meters per second. What is her kinetic energy?(1 point)

Responses

6,776 J
6,776 J

3,388 J
3,388 J

13,552 J
13,552 J

17,248 J
17,248 J

1 answer

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

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

where \(m\) is the mass of the object and \(v\) is its velocity.

In this scenario, the mass \(m\) is 56 kg and the velocity \(v\) is 11 m/s. Plugging these values into the formula gives:

\[ KE = \frac{1}{2} \times 56 , \text{kg} \times (11 , \text{m/s})^2 \]

First, calculate \(v^2\):

\[ 11 , \text{m/s} \times 11 , \text{m/s} = 121 , \text{m}^2/\text{s}^2 \]

Next, substitute \(v^2\) back into the formula:

\[ KE = \frac{1}{2} \times 56 , \text{kg} \times 121 , \text{m}^2/\text{s}^2 \]

Calculating \( \frac{1}{2} \times 56 \):

\[ \frac{1}{2} \times 56 = 28 , \text{kg} \]

Now, multiply by \(121\):

\[ KE = 28 , \text{kg} \times 121 , \text{m}^2/\text{s}^2 = 3,388 , \text{J} \]

Thus, the kinetic energy is 3,388 J.