An 80 kg skateboarder moving at 3 m/s pushes off with her back foot to move faster. if her velocity increases to 5 m/s, what is her change in kinetic energy as a result? j how much work did she perform?

1) The kinetic energy of an object is given by:

where m is the object's mass and v its speed.

By using this equation, we find the initial kinetic energy of the skateboarder:

and the final kinetic energy as well:


So, her change in kinetic energy is


2) The work-energy theorem states that the work done to increase the speed of an object is equal to the variation of kinetic energy of the object:

Therefore, the work done by the skateboarder is

B) as the temperature increases, the kinetic energy of the particles increases.|-/

The answer is  a.first and third quarters