Q2.A science teacher asked students to identify the poles of the magnet, using some paper clips made of magnetic material and a magnet. How would the students able to identify them?

i believe you are right for all except the 3rd ( look at sqdancefan his answer is much better)

8 m/s because for him to get the same amount of energy as ray is putting out, bobby, who weighs half as much as ray, needs to run twice as fast.

metals are good conductor of electricity. it has free electrons on their surface. according to electron pool theory, each atom present in a metal crystal losses all of its valence electron and as a result a pool of free is form. these pool of electrons are free to move and   conduct electricity easily   while making metal as good conductor.

the correct answer is a. the ability of electrons to flow throughout the metal.

if it's not useful, feel free to report for mistake in answer.