An electron is released from rest at a distance of 6.00 cm from a proton. If the proton is held in place, how fast will the electron be moving when it is 3.00 cm from the proton?

Respuesta :

Answer:

electron moving at 91.82 m/s

Explanation:

given data

distance d1 = 6 cm

distance d2 = 3 cm

to find out

how fast will the electron be moving

solution

we know potential energy formula that is

potential energy = [tex]k\frac{q1q2}{r}[/tex]

here k is 9× [tex]10^{9}[/tex] N-m²/C²

m mass of electron is 9.11 × [tex]10^{-31}[/tex] kg

and q = 1.60 × [tex]10^{-19}[/tex] C

we consider here initial potential energy = U1

U1 = [tex]9*10^{9}\frac{1.60*10^{-19}*1.60*10^{-19}}{0.06^2}[/tex]

U1 = 3.84 × [tex]10^{-27}[/tex] J

and final potential energy = U2

U2 = [tex]9*10^{9}\frac{1.60*10^{-19}*1.60*10^{-19}}{0.03}[/tex]

U2 = 7.68 × [tex]10^{-27}[/tex] J

and speed of electron = v

so we will apply here conservation of energy

0.5×m×v² = U2 - U1    ................1

so

0.5×9.11× [tex]10^{-31}[/tex] ×v² =  3.84 × [tex]10^{-27}[/tex]

v = 91.82 m/s

so electron moving at 91.82 m/s

Answer:

The speed of the electron is 91.86 m/s.

Explanation:

Given that,

Distance of electron from proton  = 6.00 cm

Distance of proton = 3.00 cm

We need to calculate the initial potential energy

[tex]U_{1}=\dfrac{kq_{1}q_{2}}{r}[/tex]

Put the value into the formula

[tex]U_{i}=\dfrac{9\times10^{9}\times(1.6\times10^{-19})^2}{6.00\times10^{-2}}[/tex]

[tex]U_{i}=3.84\times10^{-27}\ J[/tex]

The final potential energy

[tex]U_{f}=\dfrac{9\times10^{9}\times(1.6\times10^{-19})^2}{3.00\times10^{-2}}[/tex]

[tex]U_{f}=7.68\times10^{-27}\ J[/tex]

We need to calculate the speed of the electron

Using conservation of energy

[tex]\dfrac{1}{2}mv^2=U_{f}-U_{i}[/tex]

Put the value into the formula

[tex]\dfrac{1}{2}\times9.1\times10^{-31}\times v^2=7.68\times10^{-27}-3.84\times10^{-27}[/tex]

[tex]v=\sqrt{\dfrac{2\times3.84\times10^{-27}}{9.1\times10^{-31}}}[/tex]

[tex]v=91.86\ m/s[/tex]

Hence, The speed of the electron is 91.86 m/s.