Ans.

(i)

Sol. In order to determine n, we need two experiments where everything stays the same except for the area, so that we can investigate the results of a change in area. As for choice A, the object changes and the area does not, so that is out. In choice B, area changes from 1.5 to 3.0 cm 2 , and nothing else changes, so B is correct. Choice is incorrect because the velocity is the only thing that changes. In choice D, both A and b change, so we would not be able to tell how much change in F is due to A and how much is due to v.

(ii)

Sol. In the previous solution. We realized that experiments 4 and 6 have the property that all the input variables stay the same except for velocity v, which increases by a factor of 16, which means that p must be 2. That is, if p is 2, then an increase by a factor of 4 in v results in an increase by a factor of 4 2 in the force.

(iii)

Sol. As for choice A, experiments 1 and 2 could be used to determine p, since the velocity changes and nothing else does. Once p is determined, k can be determined by substituting in values from either experiment 1 or 2. Thus experiments 1 and 2 are sufficient. We can exclude choices B and C (not minimum sets). As for choice D, there is not enough information to obtain p or k.