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:
<h2>Answer: decreasing</h2>
An RC circuit is an electrical circuit composed of resistors and capacitors, where the charging time 
of the circuit is proportional to the magnitude of the electrical resistance 
and the capacity 
of the capacitor.
As shown below:
In this context, the electrical resistance is the opposition to the flow of electrons when moving through a conductor.
Therefore:
<h2>When a capacitor is being charged in an RC circuit, the current flowing through a resistor <u>decreases</u>.</h2>
And the correct option is b.
Answer:1.5×10 to the power of 17(unit-Hertz/H)
Explanation:V=F×Wavelength
F=V/Wavelength=3×10 to power/2×10 to power of -9=1.5×10 to power of 17
You want to draw a free body diagram of the forces on the sled in the horizontal x-direction.
If you visualize the system in an x-y coordinate plane, the force along the x-direction is the angle it makes with the x-axis multiples by the force.
The angle made with the x-axis is cosine of the angle theta.
Please see picture attached.
I would not agree with her since reflection and refraction happens only when waves hit an object. When, waves meet it is either it experiences constructive or destructive interference. Hope this answers the question. Have a nice day.
