Physics I review cram session

[beer]

I'm going to be posting questions in my review that I don't know here. If anyone has a clue send me a quarter so I can buy one from you.


"A man stands with his nose 8 cm ffrom a concave shaving mirror of radius 32 cm. The distance from the mirror to the image of his nose is...?"

I think I use 1/Di + 1/Do = 1/f, but I don't know how to find f...

 

[goog40]

f is half of the radius

so

1/8 + 1/Di = 1/16

1/Di = -1/16

Di = -16 cm

So its a virtual, upright image 16 cm from the mirror

I think that right

 

[beer]

SWEET! No where else on the Internet can you get help at 3 AM in 6 minutes!



<< f is half of the radius

I think that right >>



Is this true for all mirrrors?

 

[goog40]

Yeah, the focal point is half the distance of the radius for concave and convex mirrors(well those are the only mirrors I learned in physics)

1/Di + 1/Do = 1/f = 2/r

 

[beer]

Thanks!

I'll be back shortly with some questions, probably on electrostatics

 

[beer]

THe magnitude of the force of a 400-N/C electric field on a .02-C charge is:

I don't even think I have a basic eq for that.

 

[hendon]

can't remember the exact equation
but I think you just multiply the 2 to get a force


the eqn might look like this

F = q * field
where q = charge