This topic covers jesus who knows
This page will feature each question, as well as the options if the question is multiple choice (as noted by a "MC" tag just before the question number). Below each question will be the solution, in my own words. I attempt to be as precise and detailed as possible, but if you're still not getting something then just e-mail me and I will edit the explanation accordingly.
These are roughly ordered by their approximate difficulty (easiest to hardest), so I suggest not tackling a question unless you can solve everything above it. Please attempt the problems yourself before looking at the explanation.
(MC) If a force acting on a particle is conservative then:
1. it is not a frictional force
2. it obeys Newton's second law
3. its work is zero when the particle moves exactly once around any closed path
4. it obeys Newton's third law
5. its work equals the change in the kinetic energy of the particle
1. it is not a frictional force
2. it obeys Newton's second law
3. its work is zero when the particle moves exactly once around any closed path
4. it obeys Newton's third law
5. its work equals the change in the kinetic energy of the particle
A: This is really just a description of the "test" for confirming a conservative force. The force is conservative if all the forces if the work done in the system can be represented with W1 = -W2, where W1 and W2 are equal in magnitude so that the system has the potential to completely reverse its work (no energy is converted into thermal energy).
As such, the primary test to determine for certain if a force is conservative is to place the object in a closed path so that the starting position and final position are the same, and check to see if the net work is zero. If it is, then the force is properly conservative.
As such, the primary test to determine for certain if a force is conservative is to place the object in a closed path so that the starting position and final position are the same, and check to see if the net work is zero. If it is, then the force is properly conservative.
FINAL ANSWER: Option 3 (its work is zero when the particle moves exactly once around any closed path
(MC) A good example of kinetic energy is provided by:
1. a gallon of gasoline
2. the raised weights of a grandfather's clock
3. a wound-up clock spring
4. a tornado
5. an automobile storage battery
1. a gallon of gasoline
2. the raised weights of a grandfather's clock
3. a wound-up clock spring
4. a tornado
5. an automobile storage battery
A: Kinetic energy is the energy of motion, and only the tornado of these options actually follows that. All the other options are different forms of energy (raised weights is gravitational potential energy, the clock spring is elastic potential energy, etc.). Then again, if you made it through the last chapter then this should be fairly obvious.
FINAL ANSWER: Option 4 (a tornado)
The graphs below show the force acting on a particle as the particle moves along the positive x axis from the origin to x = x1. The force is parallel to the x axis and is conservative. The maximum magnitude F1 has the same value for all graphs. Rank the situations according to the change in the potential energy associated with the force, least (or most negative) to greatest (or most positive).
A: The work on the object is, as per usual, equal to the area under the curve. However, since we're looking for the change in potential energy for each of the situations, that value will be the negative versions of those values (ΔU = -W). For instance, if situation 2 has the largest area above the curve (and therefore has the largest work), then it will be the first situation we list since that means it has the smallest change in gravitational potential energy. Apply this principle to the other graphs and you'll get the right order.
FINAL ANSWER: 2 < 1 < 3