Electric Pendula
About points...
We associate a certain number of points with each exercise.
When you click an exercise into a collection, this number will be taken as points for the exercise, kind of "by default".
But once the exercise is on the collection, you can edit the number of points for the exercise in the collection independently, without any effect on "points by default" as represented by the number here.
That being said... How many "default points" should you associate with an exercise upon creation?
As with difficulty, there is no straight forward and generally accepted way.
But as a guideline, we tend to give as many points by default as there are mathematical steps to do in the exercise.
Again, very vague... But the number should kind of represent the "work" required.
When you click an exercise into a collection, this number will be taken as points for the exercise, kind of "by default".
But once the exercise is on the collection, you can edit the number of points for the exercise in the collection independently, without any effect on "points by default" as represented by the number here.
That being said... How many "default points" should you associate with an exercise upon creation?
As with difficulty, there is no straight forward and generally accepted way.
But as a guideline, we tend to give as many points by default as there are mathematical steps to do in the exercise.
Again, very vague... But the number should kind of represent the "work" required.
About difficulty...
We associate a certain difficulty with each exercise.
When you click an exercise into a collection, this number will be taken as difficulty for the exercise, kind of "by default".
But once the exercise is on the collection, you can edit its difficulty in the collection independently, without any effect on the "difficulty by default" here.
Why we use chess pieces? Well... we like chess, we like playing around with \(\LaTeX\)-fonts, we wanted symbols that need less space than six stars in a table-column... But in your layouts, you are of course free to indicate the difficulty of the exercise the way you want.
That being said... How "difficult" is an exercise? It depends on many factors, like what was being taught etc.
In physics exercises, we try to follow this pattern:
Level 1 - One formula (one you would find in a reference book) is enough to solve the exercise. Example exercise
Level 2 - Two formulas are needed, it's possible to compute an "in-between" solution, i.e. no algebraic equation needed. Example exercise
Level 3 - "Chain-computations" like on level 2, but 3+ calculations. Still, no equations, i.e. you are not forced to solve it in an algebraic manner. Example exercise
Level 4 - Exercise needs to be solved by algebraic equations, not possible to calculate numerical "in-between" results. Example exercise
Level 5 -
Level 6 -
When you click an exercise into a collection, this number will be taken as difficulty for the exercise, kind of "by default".
But once the exercise is on the collection, you can edit its difficulty in the collection independently, without any effect on the "difficulty by default" here.
Why we use chess pieces? Well... we like chess, we like playing around with \(\LaTeX\)-fonts, we wanted symbols that need less space than six stars in a table-column... But in your layouts, you are of course free to indicate the difficulty of the exercise the way you want.
That being said... How "difficult" is an exercise? It depends on many factors, like what was being taught etc.
In physics exercises, we try to follow this pattern:
Level 1 - One formula (one you would find in a reference book) is enough to solve the exercise. Example exercise
Level 2 - Two formulas are needed, it's possible to compute an "in-between" solution, i.e. no algebraic equation needed. Example exercise
Level 3 - "Chain-computations" like on level 2, but 3+ calculations. Still, no equations, i.e. you are not forced to solve it in an algebraic manner. Example exercise
Level 4 - Exercise needs to be solved by algebraic equations, not possible to calculate numerical "in-between" results. Example exercise
Level 5 -
Level 6 -
Question
Solution
Short
Video
\(\LaTeX\)
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Exercise:
Two pula consist of styrofoam balls coated with aluminium susped from light threads with the same suspension po see figure. The threads are lO long and the balls each have a mass of mO and carry the same negative charge. As a consequence of the repulsive force the two pula are deflected. Once they have reached the equilibrium position the distance is dO. Calculate the charge on each ball. center includegraphicswidth.textwidth#image_path:zwei-pel-# center
Solution:
Giv ell lO l m mO m d dO d GesChargeQsiC % In the equlibrium the three forces acting on the pulum ball gravitational force electrostatic force and string force add up to zero. % center includegraphicswidth.textwidth#image_path:pel-krafte# center % The triangles shaded in blue in the figure are similar. It follows: % fracsscFCsscFG fracfracdh fracfrac pi sscepsilon sscepsilonr fracQ^d^m g fracfracdsqrtell^-fracd^ fracQ^ pi sscepsilon sscepsilonr m g d^ fracdsqrt ell^ - d^ Q QPF Q sqrtfrac pi EZ ER m ge d^sqrt l^ - d^ % SolQ QP &approx QPP-
Two pula consist of styrofoam balls coated with aluminium susped from light threads with the same suspension po see figure. The threads are lO long and the balls each have a mass of mO and carry the same negative charge. As a consequence of the repulsive force the two pula are deflected. Once they have reached the equilibrium position the distance is dO. Calculate the charge on each ball. center includegraphicswidth.textwidth#image_path:zwei-pel-# center
Solution:
Giv ell lO l m mO m d dO d GesChargeQsiC % In the equlibrium the three forces acting on the pulum ball gravitational force electrostatic force and string force add up to zero. % center includegraphicswidth.textwidth#image_path:pel-krafte# center % The triangles shaded in blue in the figure are similar. It follows: % fracsscFCsscFG fracfracdh fracfrac pi sscepsilon sscepsilonr fracQ^d^m g fracfracdsqrtell^-fracd^ fracQ^ pi sscepsilon sscepsilonr m g d^ fracdsqrt ell^ - d^ Q QPF Q sqrtfrac pi EZ ER m ge d^sqrt l^ - d^ % SolQ QP &approx QPP-
Meta Information
Exercise:
Two pula consist of styrofoam balls coated with aluminium susped from light threads with the same suspension po see figure. The threads are lO long and the balls each have a mass of mO and carry the same negative charge. As a consequence of the repulsive force the two pula are deflected. Once they have reached the equilibrium position the distance is dO. Calculate the charge on each ball. center includegraphicswidth.textwidth#image_path:zwei-pel-# center
Solution:
Giv ell lO l m mO m d dO d GesChargeQsiC % In the equlibrium the three forces acting on the pulum ball gravitational force electrostatic force and string force add up to zero. % center includegraphicswidth.textwidth#image_path:pel-krafte# center % The triangles shaded in blue in the figure are similar. It follows: % fracsscFCsscFG fracfracdh fracfrac pi sscepsilon sscepsilonr fracQ^d^m g fracfracdsqrtell^-fracd^ fracQ^ pi sscepsilon sscepsilonr m g d^ fracdsqrt ell^ - d^ Q QPF Q sqrtfrac pi EZ ER m ge d^sqrt l^ - d^ % SolQ QP &approx QPP-
Two pula consist of styrofoam balls coated with aluminium susped from light threads with the same suspension po see figure. The threads are lO long and the balls each have a mass of mO and carry the same negative charge. As a consequence of the repulsive force the two pula are deflected. Once they have reached the equilibrium position the distance is dO. Calculate the charge on each ball. center includegraphicswidth.textwidth#image_path:zwei-pel-# center
Solution:
Giv ell lO l m mO m d dO d GesChargeQsiC % In the equlibrium the three forces acting on the pulum ball gravitational force electrostatic force and string force add up to zero. % center includegraphicswidth.textwidth#image_path:pel-krafte# center % The triangles shaded in blue in the figure are similar. It follows: % fracsscFCsscFG fracfracdh fracfrac pi sscepsilon sscepsilonr fracQ^d^m g fracfracdsqrtell^-fracd^ fracQ^ pi sscepsilon sscepsilonr m g d^ fracdsqrt ell^ - d^ Q QPF Q sqrtfrac pi EZ ER m ge d^sqrt l^ - d^ % SolQ QP &approx QPP-
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