# Homework Help: Electric field

1. Jan 27, 2006

### hitek131

I need help with this question if anyone can give me an idea of what to do. Any help would be greatly appreciated.

An electron is released from rest in a uniform electric field. The electron accelerates vertically upward, traveling 4.50 m in the first 3.00 micro seconds after it is released.
What is the magnitude of the electric field?

Last edited: Jan 27, 2006
2. Jan 27, 2006

### inha

Do you know what force is in charge of accelerating the electron?

3. Jan 27, 2006

### hitek131

yes it is F=E * q

I know that q = 1.62 * 10^-19, but I still have an unknown variable.

Last edited: Jan 27, 2006
4. Jan 27, 2006

### inha

You can solve the acceleration using elementary kinematics. Then you'd need to relate that force to the acceleration you solved for.

5. Jan 27, 2006

### hitek131

yes i know, you use y = 1/2at^2, but you still get unknown variables

6. Jan 27, 2006

### inha

You know everything besides E. The electron's mass is standard tabulated stuff.

7. Jan 27, 2006

### hitek131

Is the mass 9.10938188(72) * 10 ^-31?

8. Jan 27, 2006

### inha

yeah that's it. it's all algebra from here on.

9. Jan 27, 2006

### hitek131

Thank you so much!!!