Answer:
This is a conceptual problem so I will try my best to explain the impossible scenario. First of all the two dust particles ara virtually exempt from any external forces and at rest with respect to each other. This could theoretically happen even if it's difficult for that to happen. The problem is that each of the particles have an electric charge which are equal in magnitude and sign. Thus each particle should feel the presence of the other via a force. The forces felt by the particles are equal and opposite facing away from each other so both charges have a net acceleration according to Newton's second law because of the presence of a force in each particle:

Having seen Newton's second law it should be clear that the particles are actually moving away from each other and will not remain at rest with respect to each other. This is in contradiction with the last statement in the problem.
Answer:
* Experiment with a higher range of materials
* Use a galvanometer.
* Vary in number of coils of the electromagnet
Explanation:
This is an experiment of electricity and magnetism, in general the best way to improve the results are:
* Experiment with a higher range of materials
allowing to know the scope of the initial assumptions
* Use a galvanometer.
The more accurate the readings the error of the derived quantities is the less which will improve the precision of the experiment.
* Vary in number of coils of the electromagnet
Since it allows to have greater magnetic fields and therefore expand the range of measurements
Answer:
C
Explanation:
During an investigation you want to investigate different variables.
2500
--------=3125
0.8
This can be can be viewed as compression due to the direction of the arrows.
A spinning wheel
and the blade of a kitchen blender both illustrate rotation.
A child swinging on a swing
illustrates oscillation, or 'harmonic' motion.
A balloon being blown up is an example of dilation or inflation.
A sliding hockey puck demonstrates the concept of translation.