Another alternative representation — Energy bar charts

Example problem — Box on an incline

Andrew Morrison
3 min readAug 31, 2020

Here’s a problem that I once gave on an in-class assessment:

A 2.6-kg block slides down a frictionless incline from point A to point B. A force (magnitude P = 3.4 N) acts on the block between A and B, as shown in the above figure. Points A and B are 2.2 m apart. If the kinetic energy of the block at A is 10 J, what is the kinetic energy of the block at B?

This problem was copied out of a test bank and I believe that I changed all the values for everything except the initial kinetic energy. Like all the problems I’m going to show here, the solutions are easily googleable. Here’s my solution:

Solution to the above problem.

But, I don’t like this. I mean, there’s nothing wrong with it, but if the solution is already on the internet, then it’s not really a very interesting problem.

The best alternative representation for this type of question is an energy bar chart. (Some classes modify this representation and called them LOL charts.) Here’s my take on this one:



Andrew Morrison

Physics professor with research interest in musical acoustics