Answer:
The position of the person's feet. a running shoe company studying how different surfaces affect the life of a shoe tread
Explanation:
100%
The quantity is either a vector or a scalar. These two categories can be distinguished from one another by their distinct definitions: Scalars are quantities that are fully described by a magnitude (or numerical value) alone. Vectors are quantities that are fully described by both a magnitude and a direction.
Answer:
a) V = 0.82m/s
b) Vmax = 0.985 m/s
Explanation:
By conservation of energy we know that:
Eo = Ef 
Solving for V we get:
V = 0.82 m/s
To find the maximum speed we will do the same to an intermediate point where the compression is X and the distance for the work donde by frictions is given by (Xmax - X) = (0.28m - X):

Then we have to solve for V, derive and equal zero in order to find position X. After solving the derivative we get:
X = 0.1m Replacing this value into the equation for Vmax:
Vmax = 0.985m/s
The number of protons
number of neutrons=the mass number- number of protons
14-6=8