Use the image to answer the question.

An illustration shows a person running after a rabbit. The person weighs 60 kilograms, and the rabbit weighs 4 kilograms. The speed of both is 5 meters per second.

A wildlife keeper is trying to catch an escaping rabbit. Who has the greater kinetic energy, the rabbit or the wildlife keeper?

(1 point)
Responses

The rabbit because it has less mass.
The rabbit because it has less mass.

The wildlife keeper because they have a greater mass.
The wildlife keeper because they have a greater mass.

Neither one because they are moving at the same speed.
Neither one because they are moving at the same speed.

The wildlife keeper because they speed up and catch the rabbit.

1 answer

Kinetic energy is calculated using the formula:

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

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

For the rabbit:

  • Mass (\( m \)) = 4 kg
  • Speed (\( v \)) = 5 m/s

Calculating the kinetic energy of the rabbit:

\[ KE_{\text{rabbit}} = \frac{1}{2} \times 4 , \text{kg} \times (5 , \text{m/s})^2 \] \[ KE_{\text{rabbit}} = \frac{1}{2} \times 4 \times 25 = 2 \times 25 = 50 , \text{Joules} \]

For the wildlife keeper:

  • Mass (\( m \)) = 60 kg
  • Speed (\( v \)) = 5 m/s

Calculating the kinetic energy of the wildlife keeper:

\[ KE_{\text{keeper}} = \frac{1}{2} \times 60 , \text{kg} \times (5 , \text{m/s})^2 \] \[ KE_{\text{keeper}} = \frac{1}{2} \times 60 \times 25 = 30 \times 25 = 750 , \text{Joules} \]

Comparing the two:

  • Kinetic energy of the rabbit = 50 Joules
  • Kinetic energy of the wildlife keeper = 750 Joules

The wildlife keeper has the greater kinetic energy due to their greater mass.

So the correct response is: The wildlife keeper because they have a greater mass.