moving,
the sun is a different "observer"
It <span>states that the force F needed to extend or compress a spring by some distance X is proportional to that distance.
For elastic materials, they extend more in same amount of force, (as they are directly proportional), due to it's elastic nature (presence of large deforming force)
Hope this helps!</span>
Answer:
1) The maximum jump height is reached at A. 
2) The maximum center of mass height off of the ground is B. 
3) The time of flight is C. 
4) The distance of jump is B. 
Explanation:
First of all we need to decompose velocity in its rectangular components, so

1) We use,
, as we clear it for
and using the fact that
at max height, we obtain 
2) We can use the formula
for
, so

3) We can use the formula
, to find total time of fligth, so
, as it is a second-grade polynomial, we find that its positive root is
4) Finally, we use
, as it has an additional displacement of
due the leg extension we obtain,
, aprox 
Answer:
B
Explanation:
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Answer:
When the ball hits the ground, the velocity will be -34 m/s.
Explanation:
The height and velocity of the ball at any time can be calculated using the following equations:
y = y0 + v0 · t + 1/2 · g · t²
v = v0 + g · t
Where:
y = height of the ball at time "t".
y0 = initial height.
v0 = initial velocity.
t = time.
g = acceleration due to gravity. (-9.8 m/s² considering the upward direction as positive).
v = velocity at time "t".
If we place the origin of the frame of reference on the ground, when the ball hits the ground its height will be 0. Then using the equation of height, we can calculate the time it takes the ball to reach the ground:
y = y0 + v0 · t + 1/2 · g · t²
0 = 60 m + 0 m/s · t - 1/2 · 9.8 m/s² · t²
0 = 60 m - 4.9 m/s² · t²
-60 m / -4.9 m/s² = t²
t = 3.5 s
Now, with this time, we can calculate the velocity of the ball when it reaches the ground:
v = v0 + g · t
v = 0 m/s - 9.8 m/s² · 3.5 s
v = -34 m/s
When the ball hits the ground, the velocity will be -34 m/s.