Designed to accompany the Pearson Applied Mathematics Year 2/AS textbook.
To agree with Mr I Ross. The black box note on page 15 is confused/confusing. The beam does have a mass, and being massless isn't why there is no reaction force present acting on the man. We are considering the forces that act on the beam, and this reaction force acts on the man (so we don't put it on the diagram)
slide 15. If we are modelling the beam as a rod with no mass would we not have 3R = 80g? 3R = 120g includes the mass of the beam.
I am a big fan of your work but... On Slide 14 you give an answer calculated from g as 1764N. Although correct, in the Edexcel exam this will be marked wrong. All answers from g MUST be rounded to 2sf or 3sf so the only accepted answers are 180g or 1800 or 1760. (I am an examiner).
make some videos on this subject please
Slide 15 "Note: A rod has no mass, so there is no reaction force of the rod on the man, only reaction forces from the pivots." This isn't right. We ignore the reaction force of the rod on the man as we are only considering forces acting on the rod. If we were to consider the forces acting on the man we would draw and the reaction force of the rod on the man.
I don't apologise for being picky, I bow to your exactness and attention to detail in all of your work. I and all my students are indebted to you for your great work. Basically I think you are great, but wrong in this instance!
Very useful powerpoint with good examples