If he runs for 21 hours per week, how many hours does he run per day? There are 7 days in a week, so this would be 21/7. Then if he doesn't run for three days, you need to multiply this by 3.

Finding the extreme point :

Now,
f''( x ) at x = 1/3 and -1 is :

Therefore, it is maximum at x = -1 and minimum at x = 1/3 .
Hence, this is the required solution.
Alright give me a second ok
Answer: The potential energy decreases and the kinetic energy increases
Step-by-step explanation:
When a body is at rest , the Potential energy is maximum because the body is not moving and the acceleration is therefore zero but as soon as the body starts moving , it will convert the potential energy to kinetic energy , therefore the kinetic energy will therefore increase.