Question

Can anybody help with this problem?

Assuming all of the non-conservative work is due to frictional force, how do I find the frictional force and coefficient of kinetic friction for each condition?

There are three conditions. This is the data I found for each condition.

Answer 1

In each case it is the difference between the calculated energy change from the conditions (ideal) and the observed energy change from the experiment (real).

Explanation:

It depends on the intent of the exercise. If they are all subject to the same forces, then it is a comparison of the three tests to derive the common frictional force.

If it is just three examples, then as stated, it is just the difference between the calculated energy change from the conditions (ideal) and the observed energy change from the experiment (real).

For example, ALL of the calculated energies are based on frictionless conditions. So, the frictionless ratios of the energy change for Condition 1 is `66.1/66.2 = 0.9985` or `99.85%`. The indicated actual change is `199%` - I'm not sure about their ratio - I think it is inverted, or supposed to be `99%`. If we look at the relative change, the frictionless energy change is `0.15%` and the observed one would be `1%` (`100-99`). That would mean that `0.85%` of the total observed change was due to friction.

For Condition2 that would be `1.43%` change frictionless and `6%` with friction, and Condition 3 is `2.6%` and `10%` respectively.