A wave produced by a door bell?
There is a sound wave yes.
Acceleration = (change in speed) / (time for the change)
Change in speed = (ending speed) - (starting speed)
= (7.0 m/s) - (0.8 m/s) = 6.2 m/s
Time for the change = 15 seconds
Acceleration = (6.2 m/s) / (15 sec)
= (6.2/15) m/s²
= 0.413 m/s²
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
Rutherford's model of the atom (ESAAQ) Rutherford carried out some experiments which led to a change in ideas around the atom. His new model described the atom as a tiny, dense, positively charged core called a nucleus surrounded by lighter, negatively charged electrons.