A skydiver jumps out of a plane and begins to accelerate. His speed increases to 20 m/s, then 30 m/s. His acceleration slows until he reaches a constant speed of 50 m/s. Which statement correctly describes his kinetic energy during this time?

Answer 1

The kinetic energy (KE) of an object is given by the formula:

\[ KE = \frac{1}{2} m v^2 \]

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

In the case of the skydiver:

1. From 0 m/s to 20 m/s: As the skydiver accelerates to 20 m/s, his velocity increases, which results in an increase in kinetic energy.

2. From 20 m/s to 30 m/s: The skydiver continues to accelerate to 30 m/s. Again, the kinetic energy increases due to the rise in velocity.

3. Constant Speed of 50 m/s: Once the skydiver reaches a constant speed of 50 m/s, his velocity no longer changes, meaning that his kinetic energy remains constant since KE depends on the square of the velocity.

In summary, the kinetic energy of the skydiver increases as he accelerates from 0 to 30 m/s and then remains constant once he reaches a steady speed of 50 m/s. Thus, the correct statement describing his kinetic energy during this time is that it increases during acceleration and then levels off at a constant value.