Answer:
When you are running the most important force that you should understand is friction. Friction is a force that opposes movement between two objects, but for runners friction makes you faster. Friction gives you a better and more efficient way to use your energy into speed.
Answer:
All the three quantities will have non zero joules.
Explanation:
At the initial position of rest the system will have only gravitational potential energy while the other 2 quantities will be zero.
when the system reaches a height (y-h) only kinetic energy will be zero while the other 2 quantities will be non zero
At the position of (y-h/2) all the 3 quantities will be non zero.
It could result in it not being good for your joints, as well as in the long run but shouldn't cause problems when your a child. I hope this helps your question!
The answer is B.
This is because you add up all of the times (1.44s+1.70s+1.58s+1.76s) and you get 6.48 then you divide 6.48 by 4 to get the average of the times. Now you get the distance (200m) and because speed=distance/time you divide 200m/1.62s to get 123m/s. I hope this made sense :)
