## Aries 4 years ago Could someone plz help me to solve this question i don't really understand how to start the question or what actually to do..

1. Aries

An insulating rod having a linear charge density $\lambda = 40\mu C/m$ and linear mass density $\mu = 0.100 kg/m$ is released from rest in a uniform electric field E = 100 V/m and directed perpendicular to the rod. Determine the speed of the rod after it has travelled 2m. Could u plz explain how to start thx kinda suck on this question :/

2. stan

Here's a hint... It will experience an acceleration from the gravitational field, and will also experience an acceleration due to the Lorentz force.

3. Aries

So F = Eq hmmm...and force is F= ma so the equation would become ma = Eq. But i don't have the mass and charge i have there density...

4. khu

You can approach this from an energy perspective. You know kinetic energy gained due to gravity does not depend on mass. You know how to find electrical work or change in electrical potential energy. You can combine these to arrive at an expression setting kinetic energy equal to the sum of the energy changes due to gravity and the electrical field over those 2m of displacement. Hopefully the directional part of the problem is straightforward. Hint: think about charge density per unit mass

5. ac7qz

Since both force and inertia are proportional to length, you could either do this as a "per meter" calculation, or assume 1 meter and crunch it through.

6. iandominicz000

a simple answer would be that you do an energy balance or a force balance around the rod.... since you have several driving forces that are present (e.g. electric potential, kinetic, etc.).... after you establish the balance, you can get an expression where you could find the velocity of the rod...