A) 
The total energy of the system is equal to the maximum elastic potential energy, that is achieved when the displacement is equal to the amplitude (x=A):
(1)
where k is the spring constant.
The total energy, which is conserved, at any other point of the motion is the sum of elastic potential energy and kinetic energy:
(2)
where x is the displacement, m the mass, and v the speed.
We want to know the displacement x at which the elastic potential energy is 1/3 of the kinetic energy:
Using (2) we can rewrite this as
And using (1), we find
Substituting 
into the last equation, we find the value of x:
B) 
In this case, the kinetic energy is 1/10 of the total energy:
Since we have
we can write
And so we find:
Answer:
the best graph to find the acceleration is v-t since calculating the slope averages the different experimental errors.
Explanation:
The different graphics depending on time give various information, let's examine what we can get from some
Graph of x -t. from this graph we can obtain the speed through the slope, but the acceleration is not directly obtainable
v-t chart. We can get the acceleration not through the slope and the distance traveled by the area under the curve. Obtaining acceleration is very accurate since it is an average that avoids possible errors in measurements. This is the best graph to find the acceleration
Graph of a-t In this graph the acceleration is a point on the Y axis, it gives some errors because it depends strongly on the possible experimental errors.
In conclusion, the best graph to find the acceleration is v-t since calculating the slope averages the different experimental errors.
Answer:
The correct answer is A. The sun is the energy source of the surface currents in the ocean
