Electric filed physics problem. Help

[sept26bc]

Vela. I'm really confused I've been working on this for hours. I know that the gravitational and electric force have to cancel in order for the particle to be hovering.how would another force be included in the equation q/m=a/E ? or am i using the wrong equation?

 

[SammyS]

Vela. I'm really confused I've been working on this for hours. I know that the gravitational and electric force have to cancel in order for the particle to be hovering.how would another force be included in the equation q/m=a/E ? or am i using the wrong equation?

So, you need $\displaystyle \frac{|F_\text{electric}|}{|F_\text{gravity}|}=1\ .$ Correct?

How is $\displaystyle |F_\text{electric}|$ related to E and $\displaystyle |F_\text{gravity}|$ related to g ?

 

[sept26bc]

well F=ma and E=F/q so E= ma/q

|Felectric| is related to E by E=F/q
and |Fgravity| related to g by F=ma

correct?

im not understanding why you have Felectric/ Fgravity=1

 

[SammyS]

well F=ma and E=F/q so E= ma/q

|Felectric| is related to E by E=F/q
and |Fgravity| related to g by F=ma

correct?

im not understanding why you have Felectric/ Fgravity=1

If the particle hovers, what is its acceleration?

 

[sept26bc]

the acceleration would be zero because its not moving.

 

[vela]

So you know there are two forces on the particle, the force of gravity $\vec{F}_g$ and the electric force $\vec{F}_E$. You also know the acceleration is 0 because it's not moving.

What is the magnitude of $\vec{F}_g$? What is the magnitude of $\vec{F}_E$?

Now take all that info and use Newton's second law, which is $\sum \vec{F} = ma$. What do you get?