The elastic energy stored in your tendons can contribute up to 35 \% of your energy needs when running. Sports scientists have studied the change in length of the knee extensor tendon in sprinters and nonathletes. They find (on average) that the sprinters' tendons stretch 41 {\rm mm}, while nonathletes' stretch only 33 {\rm mm}.

The spring constant for the tendon is the same for both groups, 31 {\rm {N}/{mm}} . What is the difference in maximum stored energy between the sprinters and the nonathletes?
Express your answer using two significant figures in J.

26.22J

Explanation:

Conversion to metric unit

41 mm = 0.041 m

33 mm = 0.033 m

31 N/mm = 31 (N/mm) * 1000 (mm/m) = 31000 N/m

The elastics energy has the following formula

Where k = 31000N/m is the spring constant and x is the distance stretched

The elastics energy stored for athlete is

His maximum energy stored when running is 26 / 35% = 26*100/35 = 74.4 J[/tex]

The elastics energy stored for non-athlete is

His maximum energy stored when running is 16.9 / 35% = 16.9*100/35 = 48.23 J[/tex]

So the difference in maximum energy stored is 74.45 – 48.23 = 26.22 J

answer;

d. are made mostly of liquid

explanation;

-the general   composition and structure planets includes; they have a thick gas and liquid layer covering a small,solid core. mostly the gases are hydrogen and helium atmosphere and layers of liquid hydrogen. for instance neptune and uranus are examples of the outer planets, they have a core covered by ice and ammonia.

-neptune's atmosphere is hydrogen and helium with a bit of methane so there is no oxygen to breath and the interior is made up of frozen water and ammonia with a rock and iron core. thus, there is no liquid water or solid surface to survive.