Electron orbiting proton-orbital radius?

[awertag]

Electron orbiting proton--orbital radius??

Homework Statement

In the Bohr model, the electron is imagined to move in a circular orbit about a stationary proton. If the speed of the electron were 8.9e5 m/s, what would be the corresponding orbital radius?

2. Homework Equations



3. The Attempt at a Solution
Fe=ma
a=Fe/m
(v^2)/r=(kqq/r)/m
v^2rm=kqq
(8.9e5)(r)(9.11e-31)=(9e9)(1.6e-19)(-1.6e-19)
r=-2.842e-4m

I hope you can help!

--aweg

 

[SammyS]

Homework Statement

In the Bohr model, the electron is imagined to move in a circular orbit about a stationary proton. If the speed of the electron were 8.9e5 m/s, what would be the corresponding orbital radius?

2. Homework Equations



3. The Attempt at a Solution
Fe=ma
a=Fe/m
(v^2)/r=(kqq/r²)/m
v^2rm=kqq
(8.9e5)²(r)(9.11e-31)=(9e9)(1.6e-19)(-1.6e-19)
r=-2.842e-4m

I hope you can help!

--aweg

Some corrections are in red above.

Also, r should not be negative. There's one more error above which made r come out to be negative.

I assume you mean 10^‒4 when you write e‒4, etc.

 

[awertag]

is the other error that i included the sign for electron charge?

 

[awertag]

ok well now i got r=3.193e-10 meters which is positive, so that's good...but I'm pretty sure it's not right, either

 

[awertag]

and yes e5 is x10^5

 

[awertag]

oh just kidding that was correct! :D thank you so much!