Approximate Values of Kinetic Energy and Potential Energy

AI Thread Summary
The discussion revolves around calculating the kinetic energy (K), potential energy (U), and their sum (K+U) for a two-atom system in a vibrational state. The potential energy at a specific distance (r=r1) is estimated to be U = -1.2, while the total energy (K + U) is indicated as -0.4. An initial calculation suggested that K = 0.8, but this was later identified as incorrect due to a unit conversion error, as the values needed to be expressed in electronvolts (eV) instead of joules (J). The participant ultimately recognized the mistake in unit conversion as the source of confusion. Accurate understanding of energy states and proper unit usage are essential in solving such problems.
Wakko
Messages
2
Reaction score
0

Homework Statement


https://s2.lite.msu.edu/res/msu/perl_author/MI3/CH7/IMAGES/MI3_7P32.png
The figure shows a potential energy curve for the interaction of two neutral atoms. The two-atom system is in a vibrational state (i.e., a total energy state) indicated by the heavy solid horizontal line.
At r=r1, what are the approximate values of the kinetic energy K, the potential U, and the quantity K+U?

Homework Equations


Vibrational State = K + U

The Attempt at a Solution


I'm pretty sure that U = -1.2 (dotted line)
And the Vibrational State (bold line) or K + U = -0.4
Which I'd assume means that K = 0.8 but this is incorrect. I've looked at this inside out and cannot figure out what's wrong.
 

Attachments

  • physicsproblem1.png
    physicsproblem1.png
    4.2 KB · Views: 668
Physics news on Phys.org
Wakko said:
Which I'd assume means that K = 0.8 .
Looks right to me.
 
I see what my mistake was. I was putting my answer in J but they wanted it in eV.
 
I multiplied the values first without the error limit. Got 19.38. rounded it off to 2 significant figures since the given data has 2 significant figures. So = 19. For error I used the above formula. It comes out about 1.48. Now my question is. Should I write the answer as 19±1.5 (rounding 1.48 to 2 significant figures) OR should I write it as 19±1. So in short, should the error have same number of significant figures as the mean value or should it have the same number of decimal places as...
Thread 'Collision of a bullet on a rod-string system: query'
In this question, I have a question. I am NOT trying to solve it, but it is just a conceptual question. Consider the point on the rod, which connects the string and the rod. My question: just before and after the collision, is ANGULAR momentum CONSERVED about this point? Lets call the point which connects the string and rod as P. Why am I asking this? : it is clear from the scenario that the point of concern, which connects the string and the rod, moves in a circular path due to the string...
Thread 'A cylinder connected to a hanging mass'
Let's declare that for the cylinder, mass = M = 10 kg Radius = R = 4 m For the wall and the floor, Friction coeff = ##\mu## = 0.5 For the hanging mass, mass = m = 11 kg First, we divide the force according to their respective plane (x and y thing, correct me if I'm wrong) and according to which, cylinder or the hanging mass, they're working on. Force on the hanging mass $$mg - T = ma$$ Force(Cylinder) on y $$N_f + f_w - Mg = 0$$ Force(Cylinder) on x $$T + f_f - N_w = Ma$$ There's also...
Back
Top