# Recent content by Pogorz

1. ### Rotational kinematics.

I've attempted to solve the problem, found the centre of mass to be Xcm = (L+2d)/3. Not sure where to go from there, though.
2. ### Rotational kinematics.

Homework Statement i've altered this image to be easier to read. ignore problem 1 except for the information given. the picture of the rotating object is for problem 2, which is the problem i need help with http://img32.imageshack.us/img32/3690/screenshot20091121at931x.th.png [Broken] 2. The...
3. ### Work energy theorem involving a pulley

Oh! Okay I gotcha now. I just didn't include the distance that gravity was acting for on the 6kg mass. I get it now, really silly mistake. So, Work(net)=-Work(friction)+Work(gravity) <=> -5.67=-u(8)(-9.81)(2)+(6)(-9.81)(2) and solve from there? Also, could you give me another example of an...
4. ### Work energy theorem involving a pulley

Sorry, but I'm not sure if i understand the whole tension thing. What I understand is when the 8kg block pulls left on the rope and the 6kg block pulls down on the rope the tension is the same throughout the rope, and therefore as it pulls both blocks it cancels out? I just don't see how that...
5. ### Work energy theorem involving a pulley

That's my work. I don't feel familiar enough with the math text on this site yet, so scanned image will do. so, that's my work, but i'm not sure if it's right, because my friend got 0.072=mu
6. ### Work energy theorem involving a pulley

So, yeah, my midterm is on friday, and i can't even figure out how to do questions like these because i just don't understand the way my prof teaches and the textbook has nothing relevant. So far, i've used work energy theorem to find the work done to stop the block. then i wrote out a net work...
7. ### Equal Weights problem.

Okay, since the speed of the spacecraft is 0m/s relative to the aircraft, i can find the final velocity(horizontal) of the spacecraft relative to the aircraft. this is ~225m/s, which it takes 8.86s to get 1000m in front of the aircraft... so then what?
8. ### Equal Weights problem.

yeah, it would, but then once the propellor kicks in it starts accelerating to get ahead of the aircraft. and i agree, my prof really could've made this a lot less confusing by writing it out better =\
9. ### Equal Weights problem.

okay, fixed that till it get approved. image is now in thumbnail
10. ### Equal Weights problem.

problem is attached so far i've found all the variables i could, and i've noticed that the vertical acceleration is 1.5 times larger in the vertical direction when the propeller is on than when the aircraft is flying. there's just so many different variables and situations and everything that i...
11. ### I don't understand unit vectors

Okay, thanks for the help. I got some answers that do make sense. And I'd just like to point out i have no experience of any 3D vectors before monday, and anything i do know i learned through my textbooks and the internet. So thanks for the patience.
12. ### Free-falling problem.

Homework Statement A pole vaulter comes down after barely clearing the hurdle. the hurdle is at a height "H" above the top of the soft mat on the floor. The mat has a thickness of "h". when the athlete lands on the mat he slows down at a constant rate so that his speed is 0 just before he...
13. ### I don't understand unit vectors

Okay, read through unit vectors in my physics textbook. and my calc textbook. and on that site gabba posted. and my class notes. and i still don't understand what part b) is asking me to do.
14. ### I don't understand unit vectors

just to see if i'm on the right path... (Ax)(Bx) = i, (Ay)(By) = j, (Az)(Bz) = k. i+j+k = \textbf{A}\cdot\textbf{B}? My calc teacher in high school never did matrices with us, and neither did my phys 30 teacher, first week on uni and my prof expects me to know it so i'm getting the lovely...
15. ### I don't understand unit vectors

Homework Statement My prof gave me a homework assignment and i don't really understand how to do the question. You are give two vectors \vec{A}=(3,1,-3) and\vec{B}=(-2,3,4) a) Find the angle between the two vectors b) Find all the unit vectors (if there are more than one) perpendicular...