Potential difference to achieve speed

[fight_club_alum]

Homework Statement

Through what potential difference must an electron (starting from rest) be accelerated if
it is to achieve a speed of 3.0 x 10^7 m/s?
a . 5.8 kV
b. 2.6 kV
c. 7.1 kV
d. 8.6 kV
e. 5.1 kV

Homework Equations

me = 9.11 × 10−31 kg
|qe| ≡ e = 1.6 × 10−19 C
F = ma
Eq = ma
V = Eq/r

The Attempt at a Solution

I stopped at these equations and didn't know how can I use them in this case.

 

[lewando]

Are you sure the question is complete? Seems like you need a when or a where (at what time or at what distance).

 

[haruspex]

I stopped at these equations

Think about energy.

 

[fight_club_alum]

Think about energy.

Got it! Great thank you so much

For other people that may have this problem and need a solution:
Work done = difference in kinetic energy = q * (delta v)
No initial kinetic energy
(1/2* (mass of an electron) * (final velocity given)^2 = (charge of electron) * (the potential diffference or delta v)

 

[PeroK]

Got it! Great thank you so much

For other people that may have this problem and need a solution:
Work done = difference in kinetic energy = q * (delta v)
No initial kinetic energy
(1/2* (mass of an electron) * (final velocity given)^2 = (charge of electron) * (the potential diffference or delta v)

You may not have learned about this yet, but an electron-volt is a standard unit of energy, often used in preference to joules for subatomic particles.