Which list accurately identifies the hierarchy of space from largest to smallest? Solar system, galaxy, planet, universe Galaxy,
2 answers:
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Complete Question
The two isolated parallel plate capacitors be- low, one with plate separation d and the other with D > d, have the same plate area A and
are given the same charge Q.
What is the energy in the spark produced by discharging the second capacitor?
1. The same as the discharge spark of the first capacitor
2. More energetic than the discharge spark of the first capacitor
3. Less energetic than the discharge spark of the first capacitor
Answer:
The correct option is 2
Explanation:
The formula for the energy stored in the capacitor is
And generally the formula for finding the capacitance of a capacitor is
We can denote the capacitance of the first capacitor as
and denote the capacitance of the second capacitor as
Looking at this formula we can see that C varies inversely with d
as D > d it means that
Since the charge is constant
i.e U varies inversely with C
So =>
This means that the energy of spark would be more for capacitor two compared to capacitor one
The correct option is 2
Answer:
Its speed is maximum and its acceleration is zero
Explanation:
- Concerning the speed:
In a simple harmonic motion, the speed can be determined through the law of conservation of energy. In fact, we have that the total mechanical energy of the system, which is sum of elastic potential energy U and kinetic energy K, is constant:
where k is the spring constant, x is the displacement, m is the mass and v is the speed.
We see that when the displacement is 0, x = 0: this means that the elastic potential energy U is also 0, therefore the kinetic energy K is maximum, and so the speed v is also maximum.
- Concerning the acceleration:
According to Newton's second law, the acceleration of the system is proportional to the net force:
the net force is just the restoring force of the spring, given by Hooke's law:
So, the acceleration is
and we see that when the displacement is zero, x = 0, and so the acceleration is also zero.