We got a message while we were at work the other day. It was a bit weird and it sort of threw a monkey wrench in to my day. Some foolish thief tried to break in to the house the other day. Of course they are locked up for it and probably getting examined to see how much sense that they have. Of course we have an adt security camera staring right down at the front door. It is not like we are hiding this fact. We got one of those signs that say this house is protected by ADT. Of course I guess the thief might have thought that was a big lie, but it was not a big lie. We really had ADT and they called the cops. » Continue Reading
I was reading some important information about upcoming changes to my electricity service. I am not sure how much the changes impact me, but it has got me to wondering if I might not be able to get a better deal for internet from another provider in the area. It is something that I should probably look into, because I would be much happier if I knew that I were paying the best price for electricity. I have a lot of home improvement projects that I need to get to this summer, since I am going to have more free time, and I am going to be working less at the office.
I am going to enjoy getting things done on the house. » Continue Reading
With so many chocies in energy providers in Texas, it makes you wonder what they’re doing right compared to the other states! I’ve moved from state to state over the years and even if a couple of the others have several different energy companies as Texas does, none of them have the number that the Lone Star has brought together. It’s the abundance of energy companies which has given rise to such great prices for the residents here while the competition continues to drive prices down. It’s partially why I’ve chosen to call the state home for so long – cheap bills!
All in all, it effects everything. » Continue Reading
I live in Texas and I have been very interested in recent developments with the price of oil. It is kind of weird that the prices of oil have gotten so low, and I guess that maybe the Saudi government knew what they were doing when they decided to not lower production, in order to keep the price stable. I am not sure Russia was very happy about that situation, since their economy is so dependent upon oil exports. Anyway, I want to learn more here about how the decrease in oil prices will affect the local energy prices in Texas.
I am sure that there has to be some connection here, but I am not sure if it would cause an increase in prices, or if it would cause a decrease prices. But it is something I am very interested in. I am trying to learn more about economics in general, and how politics across the world affect the economy. It is a lot more complex than I would have ever guessed before I started reading about the subject. But I am convinced I am going to be able to make progress on making sense of all of this, if I am able to continue to commit a lot of my time to learning about the subject. It is important to me to have a grasp of what is going on in the world, because I think that we all have a duty to be informed as citizens. Our country cannot run properly if our citizens are not informed, and I do not mean that they should watch the major news networks. All of those networks are biased and they dumb down stories. It is awful, and I wish that something could be done about it. But I doubt that there is anything to do.
- A wheel (mass M, radius R) rolls with speed v and angular velocity w (v=ωR) and collides elastically with a wall. Immediately after the collision it has v away from the wall, but the same ω as before – so it’s skidding, not rolling.
Friction at the floor will eventually re-establish rolling motion, by doing negative work on the system and applying a torque that will change ω.
What is the new speed v’ away from the wall when rolling motion is re-established?
Answer by RickB
That’s an interesting question!
First, let’s set up direction conventions. Let’s say:
* The wall is on the left, so the wheel bounces off to the right. Let’s call “rightward” the positive linear direction.
* Let’s call “clockwise” the positive angular direction. (That means the wheel’s rotation is negative immediately after the bounce.)
During skidding, the force of friction is more or less constant (given by: (normal force)×(coef. of sliding friction)), so we can say that “Ff” is the (constant) force of friction during the skidding phase.
The force Ff produces a torque on the wheel, in the amount of: τ = (Ff)R. (This is a positive torque, since Ff points to the left and therefore tends to drive the wheel clockwise.) We know that the angular acceleration is given by:
α = τ/I = (Ff)R/I
where “I” is the wheel’s moment of inertia. I’m not sure what kind of wheel this is, but its moment of inertial can be represented as: I = βmR², for some “β” that depends on how the wheel’s mass is distributed. (It’s some constant between 0 and 1.) So we can write:
α = (Ff)/(βmR)
At the same time, the ball’s linear acceleration is:
a = -Ff/m
(Here we use negative Ff, since the force points toward the left)
With these two values, we can write the ball’s angular and linear velocities as a function of time:
ω(t) = ω0 + αt = ω0 + (Ff)t/(βmR)
(where ω0 is the ball’s angular velocity right after collision)
v(t) = v0 + at = v0 + (−Ff/m)t
(where v0 is the ball’s linear velocity right after collision)
We are also given that ω0 = −v0/R, so we can rewrite the ω(t) equation as:
ω(t) = −v0/R + (Ff)t/(βmR)
Now, at some time t′, rolling is re-established. That means:
v(t′) = ω(t′)R
v0 + (-Ff/m)t′ = −v0 + (Ff)t′/(βm)
t′ = 2(v0)mβ/[Ff(1+β)]
Now plug that value back into the “v(t)” equation:
v′ = v(t′) = v0 + (-Ff/m)2(v0)mβ/[Ff(1+β)]
= v0 – 2(v0)β/(1+β)
= v0(1 – 2β/(1+β))
So for example, if you assume that the wheel has a uniform density, then β=½, in which case v′ = v0/3.
- I own 1 unisex deep v and 1 unisex regular v-neck. I know that the regular v-neck runs slightly bigger than the deep, but how do they compare to the regular t-shirts as far as fit? I wear an xs in both v-necks for reference.
Answer by Benjamin
The fit of most of the crew necks (2001, BB401, TR401, 6401) is closer to the regular v neck (2456)
Go with XS in unisex styles and a S in womens.
- What current would flow in an ordinary 110 V household circuit, if a 1210 W hair drier and a 700 W microwave oven were operating simultaneously on this line?
Answer – 17.36 A
How much current would the hair drier and microwave from the previous question draw, if they were connected to the 110 V line in series?
Answer by Kim
IF you assume they act like simple resistors, then you can figure out their individual resistances using P = I^2 R. In the first part, you know P and I.
Once you know their resistances, when you put them in series you add their resistances. So then you can find I from I = V/R.
But I’m not sure these devices will really act like pure resistors because they have motors in them. There could be an inductive component.
I did not realize that when I went from my local cable company that I would be getting those great music channels on my new satellite programming. I was so excited because I was actually getting the satellite radio that a lot of people pay a lot of money for. However, this was included in the large package that I was paying a lot of money for. I was happy to see that one of my favorite radio talk show hosts was even included in my http://directsavingstv.com/ package and I could not believe that they would be able to include him in the package that I was getting. » Continue Reading