Calculating Work to Stop a Moving Electron

  • Thread starter Thread starter strugglin-physics
  • Start date Start date
  • Tags Tags
    Electron Work
AI Thread Summary
To calculate the work required to stop a moving electron, the relevant formula is W = ΔKE, where ΔKE represents the change in kinetic energy. The initial kinetic energy (KE) of the electron is determined using the equation KE = 1/2 mv^2, with the mass of the electron being 9.11×10^-31 kg and its speed 1.86×10^6 m/s. Since the final kinetic energy is zero when the electron stops, the work done is equal to the negative of the initial kinetic energy. The discussion emphasizes that there is no potential energy involved in this scenario. Ultimately, the calculation simplifies to determining the initial kinetic energy to find the work needed to stop the electron.
strugglin-physics
Messages
47
Reaction score
0
How much work is required to stop an electron (m = 9.11×10-31 kg) which is moving with a speed of 1.86×106 m/s?

Ef-Ei=W
Kenetic E - Potential E = Work
I don't think there is any potential energy in this case...

I'm a bit stuck. Any suggestions?
 
Physics news on Phys.org
Keep going. W = \Delta {KE}, so what's the kinetic energy of that electron?
 
is the change in kenetic energy 1/2mv^2?
 
The initial KE of the electron is 1/2mv^2; the final is zero. So, yes, the change in KE is (minus) 1/2mv^2.
 
Great thank you that was a whole lot easier than I made it out to be!
 
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 '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