Anyone taking/taken Engineering Physics? Options

[Coomer]

I'm in my first quarter of a year of engineering physics, and I'm always in class every day and paying attention every day, but I just can't grasp the concepts...it all makes sense up on the board when the teacher's doing it, but as soon as I get home and attempt to do the homework, I can't even begin to comprehend what's going on.

I even fully read the textbook chapters and look over all my notes and look up stuff on Google, but at the end of the night I just want to kill myself because I often work for 4-5 hours and get maybe 2 out of 10 problems right. And our homework is online so I face the reality that I'm completely stupid immediately rather than feeling good for the rest of the night and then realizing this fact in class.

Has anyone taken this class? If so, how'd you get through it? Does anyone know of any online resources for learning physics?

I just need to get through it for a couple more weeks, and then I'm changing my major for sure.

[orvillescelica]

try drawing free body diagrams, they help!! describe all forces on al the blocks, it will help you visualize what forces are in the y or x direction.

well, in this example problem follow the strings... block B is pulling down on the string with a force of 21 N. So you need a minimum of 21N pulling on the other string to keep it from falling. The force that is pulling back in the direction of the string is friction. The force of friction in the string direction is F= (mu)Fn. So the force of friction needs to be 21N, and that must equal the normal force of block A and C times the coeff of friction given. So you have:

21N=(0.2)(44N+c)

comes out to c=61N


for part b, lets assume that there was no friction, then block b would fall at 9.81 m/s^2 because there is nothing opposing its fall. Thus it would drag block A with it at the same acceleration. But with friction this isnt the case.

So using F=ma, find the mass of block B assuming no friction. Thats just 21N=(m)(9.81)

now add friciton, (Force of B)-(Force normal of A)(coeff of friction)=(mass of B)(a)

solve for a

**edit** if this is wrong, someone please correct me. I havent done this is a while

This post has been edited by orvillescelica: Nov 19, 2004 - 12:16 AM