Hi Everyone,

I have been going through the Day 4 Session 2 Performance video lecture and have come unstuck at a particular point while trying to proof my answer for question 1 on page 169 for exercise 5.8. I would like to get this clear in my mind as I feel it will help me in the exam to make sure that I truly do have the right answer and can therefore move on from the question with peace of mind.

I just don't know where I am going wrong. On the video at the 40 minute and 45 second mark, Bob starts to explain how to prove the answer to make sure you have got the answer right. Am I correct in assuming that the answer to that final proof equation should always be equal to the required CoG of 2680 or very close to that for an aft limit shift, add or subtract weight problem? It is confusing me because I know the 8 kg weight to shift answer is right but then my proof answer comes out to be 2638.

I have tried to prove my answer for exercise 5.8 page 169 but I just can't seem to get to an answer of 2680 so I think I am actually doing something wrong or missing a crucial detail somewhere in relation to my thinking? This is the only part of the whole video that I am not fully understanding.

Please help!

Present Weight 2550kg Present Moment 687 index units
Take 8 from rear (-8) -4 index units
Place 8 in nose (+8) +4 index units
Weight stays the same 683.4 index units

Present CofG = 6834000 ÷ 2550 = 2680mm

I thought i had double checked and rechecked all of my working out properly before posting but clearly not. Thank you, i will make sure i triple check my work next time before posting