Force on electron in an upward electric field

jegues · Jan 23, 2011

Homework Statement

See figure attached for problem statement.

Textbook figure 22-55: an electron launched at angle θ0 from the x axis into a region with uniform field E pointing upward along y, with a detecting screen parallel to the y axis at x.

Homework Equations

The Attempt at a Solution

I think my main source of confusion is this problem is how the force is acting on the electron.

The picture shows that the electric field is pointing straight up, but since its acting on an electron (negative charge) the force will be in the opposite direction correct? (i.e. straight down)

If this is the case the acceleration the electron experiences is a vertical acceleration downwards.

Anyways, here's my attempt at the problem,

Handwritten physics working on grid paper: a diagram of an electron launched at 2.10e6 m/s at 40 degrees with a 3 m horizontal distance and an upward electric field E, followed by equations for velocity components, acceleration a = Eq/m, and computed values.

Did I make any mistakes?

cupid.callin · Jan 23, 2011

Check your calculation for V_yfinal, A is downwards and therefore negative

jegues · Jan 23, 2011

cupid.callin said:

Check your calculation for V_yfinal, A is downwards and therefore negative

Wait, I'm getting the same number, 0.83m/s ?

cupid.callin · Jan 23, 2011

i thought its 083! sorry,

everything else seems fine

what's the correct answer?

jegues · Jan 23, 2011

cupid.callin said:

i thought its 083! sorry,

everything else seems fine

what's the correct answer?

I don't know it's not given. I was wanting to check that as well.

Force on electron in an upward electric field

Homework Statement

Homework Equations

The Attempt at a Solution

Discussion

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