Uncertainties in the momentum and kinetic energy of the proton?

AI Thread Summary
The discussion focuses on calculating the uncertainties in the momentum and kinetic energy of a proton within a tin nucleus, given its confinement in a sphere with a diameter of 2.2 x 10^-14 m. The uncertainty in momentum is calculated as approximately 4.77 x 10^-21 kg(m/s) using the uncertainty principle. However, there is confusion regarding how to determine the uncertainty in kinetic energy without a specified time. It is suggested that the kinetic energy can be derived from the momentum calculated earlier. Understanding the relationship between momentum and kinetic energy is key to solving the problem.
Physics321
Messages
12
Reaction score
0

Homework Statement


A proton in a tin nucleus is known to lie within a sphere whose diameter is about 2.2 multiplied by 10E-14 m. What are the uncertainties in the momentum and kinetic energy of the proton?

Homework Equations


delta(x)*delta(p) >= hbar
delta(E)*delta(t) >= hbar


The Attempt at a Solution



I understand the first part finding the uncertainty of the momentum, which is simply. . .

1.05E-34 J(s) / (2.2E-14 m) = 4.77E-21 kg(m/s)

I don't however, in any way understand finding the uncertainty in the kinetic energy. . . Howe are we suppose to know this if we aren't told the time (or does that matter). I know the answer should be something times E-14, but I would like to know how to modify and manipulate this equation (delta(E)*delta(t) >= hbar.

Any help would be appreciated.
 
Physics news on Phys.org
I think you just need to find the kinetic energy corresponding to the momentum you have calculated.
 
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