Answer of the HSC 2018 paper - question 27a (1 Viewer)

[Kathy358]

This is the screenshots of both the question and sample answer


My first thought when seeing the question is that I had no idea what the errors come from (lol) but then I thought I could resort to say that the ruler is not long enough to cover the entire range and this can lead to parallax error. However, when looking at the answer, I am 100% sure that I was completely wrong. I also don't understand the sample answer, specifically the effect of the first one "Camera is off centre". Why does it appear to be moving faster? Sorry if this sounds silly but I don't have much experience in handling a camera. I don't understand the effect of the second one either. Why is the distance greater? Moreover, I have no idea why the camera and the ruler are regarded as being "non-linear". Doesn't they look to be parallel to the wall? Is my understanding of non-linearity flawed here?
It's a bit frustrating to me that if I were to do this question, I would end up getting 0 mark for this. Is there any way I can do to help me improve skills in solving this type of question? (I'm sitting the HSC in 2020)
Thank you so much for taking the time reading this.

 

[Drdusk]

I'll write up the first one later.

For the second one imagine your holding a ruler and trying to measure the height of a tree. If your standing 10m away from it the whole tree might fit inside the ruler which will tell you the tree is 100cm high when in reality it is 6 meters high. The same way your ruler needs to be close to the tree, the ruler in this must be closer to the trajectory.