# Recent content by 012anonymousx

1. ### Archived Transformation of Gravitational to Kinetic Energy

I am not following the template for the reason that this is a generic question. Consider that the change in kinetic energy is 1J. Suppose further you have two particles, both of equal mass that are gravitationally attracted to each other (and the change in energy comes from the fact that they...
2. ### Center (in y direction) of Mass of 3D pyramid

Got it got it got it! 3.6 is constant. Brb [EDIT] Works. You made me think of it. I was looking at integrating from the top and wrote out eqn to reverse and realized... wait a minute, i'm scaling the width but its constant... TYVM.
3. ### Center (in y direction) of Mass of 3D pyramid

That shouldn't matter. Take the center of mass from 7.85m from the top. Interestingly. 7.85m is the middle of the triangle.
4. ### Center (in y direction) of Mass of 3D pyramid

Homework Statement A monument is made from stone blocks of density 3800kg/m^3. The monument is 15.7m high, 64.8m wide at the base, and 3.6m thick from front th back. How much work was required to build the monument? (Hint: find ycm). Homework Equations ycm = (1/M) * ∫ydm, M = mass total...

Thank you!
6. ### Moments - How are they actually calculated?

Moments -- How are they actually calculated? Hello, I have a question. Is the moment calculated: Force times the distance or Force's perpendicular component (to axis) times the distance. For example, lets say I have a stick. Pulling on it is not moment. So if I push at the...
7. ### Physics of a TreadWheel [Abstract Concept?]

Yeah, I figured that after I thought about it a lot. So F = ma, and we have the tangental force at the radius of the bigger circle. But f = ma, and once again, we don't have m and we shouldn't even have a. The circle should not be accelerating. The angular velocity anyway.
8. ### Physics of a TreadWheel [Abstract Concept?]

Homework Statement [EDIT] Cleaned up the problem. A tread wheel crane is an ancient device used to lift heavy objects. It consists of a large circle (like a hamster wheel) for a person to walk inside. The large circle connects to the middle where there is a small circle that is attached a rope...
9. ### Challenge Problem

Homework Statement A person standing at the top of a hemispherical rock of radius R kicks a ball (initially at rest on the top of the rock) to give it a horizontal velocity v. What is the minimum initial speed to ensure the ball doesn't touch the rock? Homework Equations x^2 + y^2 = r^2...
10. ### Error Propogation

Ugh... I'm just a first year. My statistics class is next year and I only have to follow standard rules for now, so even if I wanted to, I probably shouldn't look up formulas, especially when there are apparently more than one way to do something (as per yourself). Also, why should one thing...
11. ### Error Propogation

This isn't a homework problem. I'm just having ALOT of trouble understanding how to do error propogation. [EDIT] These are actually lab results. But its not a "homework" question. Its how to do uncertainty. Just trying to be clear. Consider we take different measurements of an objects...
12. ### Structural Engineering Stress Question

Ah, I appreciate it. I got it, thanks a lot.
13. ### Structural Engineering Stress Question

Aha! Thank you... that clarified a lot. Okay, I have another really difficult question: again, this is problem set so please push in the right direction. A mercedes-Benz weighing 4000kg and travelling 160km/h runs into a concrete post. Assuming all kinetic energy is used to crush the low allow...
14. ### Structural Engineering Stress Question

Interesting... Sure, my solution was really close, but only because I appeared to have picked a good diameter. I could easily have picked a bad diameter and got it wrong. So what was fundamentally wrong with my solution? Also, I notice that one cannot solve for the area (diameter) or the...
15. ### Structural Engineering Stress Question

Wait... whaa...? How can you not assume any diameter..? What is going on here...what formula is that. Isn't the length you can go down heavily dependent on the diameter of the piano wire? That formula doesn't assume anything. You could lower a 0.1cm diameter wire or a 1m wire... But if you...