Hi everyone, just a quick question..
I tried this problem using Newtons laws, not conservation of energy, and I got an answer exactly half of what the correct answer is, and I'm not sure why. Here is what I did:
Net force = zero once the spring is compressed, therefore
mg - kx = 0
mg = kx...
Oh I see now! I completely forgot that net force would be the sum, and so what I really calculated was Ftension + (-mg). That makes sense, thanks so much. My textbook defined g to be a positive number as well, but that lead me to another question that is perhaps semi-related to this one...
If I...
Thanks for your response! I recognize that tension acts up, as that is actually how I realized my answer was incorrect (because tension is acting upwards, and upwards is positive, I should have gotten a positive value instead of my negative one). Gravity acts downwards, I agree, and that's also...
So the first thing that I did was solve for the acceleration of the elevator, given the velocities and distances given in the question. My question regarding this issue is not so much the procedure needed to solve the question, but rather the sign conventions for the values given and calculated...
Hi everyone. I was testing the pH of water that had alka seltzer placed in it. I used Bromothymol blue indicator to see the pH. The color changed to yellow, which suggests that the water was now acidic. I assume this is because of the CO2 bubbles that form which can acidify the H2O. Am I...
Hi martin. Thanks for your time and response. Regarding your reply, isn't solubility relative? When the term 'well soluble' and 'insoluble' are used, aren't they are referring to their solubility in a particular solvent? A compound may be insoluble in one substance, but greatly soluble in...
Hi everyone. I am a beginner in chemistry (introductory) so my knowledge is pretty limited when it comes to this subject.
From what I have been taught, like dissolves like, meaning polar dissolves polar and non-polar dissolves non-polar. The electronegativity difference of AgCl is around 1.3...
Wow, thanks for your reply! I understand now that I should have been more clear in my statement and accurately distinguish what I was referring to.
On a side note... I was also thinking that there are limits to what you can express with one function notation. For example, if I were to say f(x)...
Ah okay. Thank you two so much! Really silly mistake on the third one now that I look back on it...
So to clarify, if the statement is f(x) = x^2, all this means is that whatever is put into the brackets of f(x), it must follow the x^2 after it. It is okay to use variations of f(x) to explain...
Hi everyone. I'm getting slightly confused about the general function notation used. I was wondering if the name of the function were to change if there was an edit to the equation.
What I mean is let's say we have the graph f(x) = x^2. If I were to vertically stretch this equation by a factor...
Hi everyone, I just wanted to say a warm thanks for all of the help I've received on this forum. It's pretty amazing to see the dedication of the mentors, other helpers, their efforts in their replies, as well as the patience they have towards questions and homework. I've completed my Physics II...
Ah okay, thank you very much for your reply! It makes sense that if you ingest something radioactive then you will begin to emit radiation. I guess I was overthinking the question because I thought since technically these particles are passing right through you, you are emitting radiation behind...
Hi everyone. I was thinking about the question that I stated in the title. If you are exposed to radiation, such as alpha and beta particles, you don't emit radiation. The alpha particles are merely stopped because they don't have a high penetration. The beta particles pass through your body and...
Right. So that means that for the formula:
T is always the time measured by the stationary observer
TO is always the time measured by the moving object
And my reasoning is that TO must be smaller than T because TO's time is dilated. Time moves slower for the moving object, thus it's value for...
I just realized that what I did in post #9 was incorrect...
In the formula t = to / √1-(v/c)2
the √1-(v/c)2 section is always less than one. That means that t > to right?
I really want to make the time dilation formula work for this problem. I read that to is the proper time, and that the...
Ah okay, thank you two very much for your time. I greatly appreciate it.
After seeing your post I re-tried it using the time dilation formula, and so I did:
t = to / √1-(v/c)2
0.002142 = to / √1-(v/c)2
to = 0.00299
And then using the distance = speed x time formula
d = 2.1 x 108 x 0.00299
d =...
Just to clarify... the question says that the man who is flying above Earth measures the distance between Toronto and Montreal to be 450 km. That is, from his reference frame the distance is 450 km, not shorter. Right?
Doesn't that mean that the real distance, which is the distance in the rest...
I think I understand now... I saw a video that stated Lo is referred to as a proper length. The individual measures proper length when they are at rest to the object that they are measuring.
So in this instance, I am stationary relative to the object I am measuring (In this case, the object is...
The equation for length contraction is:
L = Lo √1-(v/c)2
I didn't know that this formula could be applied to distances between places. I was under the impression that it only referred to the object that is moving. I thought it meant that Lo is the length of an object that is at rest, and that L...
Homework Statement
A man is flying with a speed of 0.7c and at a height 1 km. During his flight, he measures the distance between Toronto and Montreal to be 450 km. What is the real distance between them.
I don't think the answers are based on real life, they are just examples of places...
Hi everyone.
I've been doing a lot of reading regarding electric potential and electric potential energy. Unfortunately, I have a lot of confusion regarding this topic, as I keep receiving different information. My main confusion is regarding the signs, positive or negative, of work and it's...
Am I supposed to be using the torque value I got? I thought about the question some more and tried using Newtons second law but I realize now that torque and force are two different units. The chapter I got this question from didn't include information on angular acceleration, plus I haven't...
That is the area that I am struggling with. I assumed that the torque value I calculated (1.274) was the tension, but that is not right. I thought about possibly calculating the torque around the 100 cm end, rather than the 0 cm end, so that I could have tension as a variable in my torque...
Homework Statement
A meter stick with a mass of 260 g is supported horizontally by two vertical strings, one at the 0-cm mark and the other at the 90-cm mark
A) What is the tension in the string at 0 cm
B) What is the tension in the string at 90 cm
C) The string at the 90-cm mark is cut. What...
Thank you for your time, and sorry for the late response - I got caught up in some other subjects...
So is this what occurs when one were to accelerate at a rate greater than the gravity acting on them? It would feel as though they were getting pushed away? If so... why does this happen? I am...
Thank you very much for your response.
I am glad my work checks out, though I can't seem to wrap my head around why the answer for part b is negative..
Included in that is my confusion regarding which direction these apparent weight forces should be pointing:
My first guess is that for a)...
Homework Statement
What is the apparent weight of a 70-kg astronaut 3800 km from the center of the Earth's Moon in a space vehicle when
a) Moving at a constant velocity
b) Accelerating toward the Moon at 2.9 m/s^2?
State direction in each case
Homework Equations
wt = m(g+a)
wt = m(g-a)
Fgr =...
Hi everyone.
I read from:
https://www.nucleonica.com/Applet/NaturalRA/Button5/page5.html
that inside the human body, 4400 of K40 atoms disintegrate every second through radioactive decay. Of this decay, 11% (480) results in gamma radiation, and 50% of that 11% (240) escapes the body.
My...
Thank you very much Doc Al and Chester, I truly appreciate the patience and effort you two have in helping me understand this concept. I'm not entirely sure how to reply to both of you in one of my own, but I am very grateful nonetheless. Sorry for the late reply, I decided to think about what...
Thank you so much for your time and reply once again!
Understanding that the weight force and the upward pulling tension force are not third law pairs cleared up a lot of my confusion, but I still have a couple more questions regarding this:
Do the two tension forces pulling down on the pulley...
Hi everyone. I found this image online that made me question a couple of things that might be a bit humiliating to ask:
I always thought that tension is simply a pulling force, meaning that the mass is suspended because the tension force pulling the mass is equal to the weight force of the...
Ah okay, thank you so much for your reply.
So it isn't necessarily wrong to say that a curved line on a displacement time graph represents constant acceleration or constant deceleration, but in some cases that curved line could mean an increasing or decreasing acceleration instead, right? I'm...
Sorry, it's just what I've been taught in class. I was told that those curved lines on a displacement time graph would imply a constant acceleration or constant deceleration. I'm assuming that is wrong?
What would constant acceleration look like on a displacement-time graph, then? Or what does...
Hi everyone. I just have a very quick question regarding position time graphs and velocity time graphs for a pendulum.
As we know, at the maximum displacement, the acceleration is at its maximum and the velocity is zero, and vice versa when the displacement is zero.
When we put this...