A hawk is chasing a sparrow. At the beginning of the chase, the hawk’s kinetic energy is 5.1 Joules. At the end of the chase, the hawk doubles its speed. What is the best prediction for its kinetic energy at the end of the chase?(1 point)

Responses

2.55 J
2.55 J

10.2 J
10.2 J

5.1 J
5.1 J

20.4 J
20.4 J

1 answer

Kinetic energy (KE) is given by the formula:

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

where \( m \) is mass and \( v \) is speed.

If the hawk doubles its speed, let's denote the initial speed as \( v \). The initial kinetic energy is:

\[ KE_{\text{initial}} = \frac{1}{2}mv^2 = 5.1 \text{ J} \]

When the speed is doubled (i.e., the new speed is \( 2v \)), the new kinetic energy will be:

\[ KE_{\text{final}} = \frac{1}{2}m(2v)^2 = \frac{1}{2}m(4v^2) = 4 \left(\frac{1}{2}mv^2\right) = 4 \cdot KE_{\text{initial}} = 4 \cdot 5.1 \text{ J} = 20.4 \text{ J} \]

Therefore, the best prediction for the hawk's kinetic energy at the end of the chase is:

20.4 J