The results of the calculation are;
a) The feet spends 0.41 s in air
b) The highest point above board is 2.62 m
c) The velocity when her feet hit the water is 7.2 m/s
<h3>What is the time spent in air?</h3>
From the data presented;
v = u + at
But v = 0 m/s at the maximum height thus;
0 = 4 - (9.8 * t)
4 = 9.8 * t
t = 4/9.8
t = 0.41 s
b) from;
h = ut - 1/2gt^2
h = (4 * 0.41) - (0.5 * 9.8 * (0.41)^2)
h = 1.64 - 0.82
h = 0.82 m
The total height above board = 0.82 m + 1.8 m = 2.62 m
c) The total time in air is obtained from;
h = ut + 1/2gt^2
u = 0m/s because she dropped off the board
h = 1/2gt^2
2.62 = 0.5 * 9.8 * t^2
t = √2.62/0.5 * 9.8
t = 0.73 seconds
Hence, the velocity when her feet hit the water is obtained from;
v = u + gt
when u = 0 m/s
v = gt
v = 9.8 * 0.73 s
v = 7.2 m/s
Learn more about velocity:brainly.com/question/13303224
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The potential energy is stored in the chemical bonds of the food. When those bonds break up during the metabolic processes, the energy is released. After that, that energy is stored in the Adenosine Triphosphate bonds aka ATP. The simplest way to think is to think of food as the tightly bound atoms. When the chemical bonds between those atoms break, the stored energy in that food is released.
Answer:
a) 
, b) 
Explanation:
a) The Hooke's law states that spring force is directly proportional to change in length. That is to say:
In this case, the force is equal to the weight of the object:
The spring constant is:
b) The length of the spring is:
The red box must way more. Gravitational potential energy is the product of a an objects mass times the acceleration due to gravity (which is constant on earth) times its height. Since the objects are on the same shelf they are at the same height, and since gravitational acceleration is constant as long as we stay on planet earth, then the mass is the only possible thing that could have changed. This means that the red box must weigh more than the blue box.
