You can find the link to the video for numerical example attached herewith kzbin.info/www/bejne/l2fUdKGur7mIe8k

Glad it was helpful!

Thank You

Dear Praveen, I am glad that you pointed out this. Your answer is absolutely correct. 84.86 mm is the right answer. Actually, I must have written the answer for the previous question. Also, do let me know your faculty number.

Faculty no - 18MEB018

Again a very good question Praveen. Actually, what you have learnt till now is that your stress is load/force divided by the perpendicular area. However, this is not how we define stress. Stress is always defined at a point and not area. Although what you are saying is absolutely true for a rectangular cross section beam but not for all cases. You must have studied in your sophomore year that we define the state of stress, that's the proper way of defining stress and not just load by area. However, in this case in order to simply calculations and to be on the safer side we have taken t*l. I hope this answers the question. In case, you still have doubt about this feel free to ask again and again and again until its crystal clear.