Question

3. An electron orbits the nucleus at a distance of 5.3x10-11 m and makes 6.6x1015 revolutions per second.

find centripetal force

Answer 1

@Loser66 i am a bit confused with this one

Answer 2

what do you get so far?

Answer 3

i think the radius is 5.3 x 10^-11 and i understand what the 6.6x 10 ^15 revolution per second is?

Answer 4

i dont have mass either

Answer 5

i dont know, i think 1 second?

Answer 6

so t is( 6.6 x 10 ^15) / 1 second

Answer 7

@ganeshie8

Answer 8

I dont know what to do with this, I think i have time and i know the radius but i dont have mass.

Answer 9

would i use a constant for mass of an electron

Answer 10

https://www.google.co.in/search?q=mass+of+electron&oq=mass+of+electron&aqs=chrome..69i57j0l3.2812j0j1&sourceid=chrome&ie=UTF-8

Answer 11

a = w^2R

F = ma

Answer 12

dont we use centripetal force formulas?

Answer 13

we dont have w either?

Answer 14

use watever u have

Answer 15

or knw :)

Answer 16

would we use

w = 2 (pi) / r

f = m r w^2

Answer 17

i mean w = 2 (pi) r / t

Answer 18

wat is centripetal force formula ?

Answer 19

f = m v^2 / r

Answer 20

or f = m w^2 R

Answer 21

w = angular velocity

Answer 22

anything wil do
use watever u r at peace wid :)

Answer 23

how do i find w

Answer 24

w = 2 pi f = 2*pi*6.6x10^15

Answer 25

how would that be times by i thought we divide, I still dont understand the 6.6x1015 revolutions per second.

Answer 26

ever heard of the term 'frequency' beofore ?

Answer 27

a little not too much in chapters

Answer 28

@Loser66 interpretation looks simple, see if u get it

Answer 29

i liked ur interpretation relating frequency directly to velocity :)

Answer 30

btw, thats angular velocity w.
wat we talking so far

Answer 31

okay so I can use
w = 2 (pi) / r

f = m r w^2

r is given the 6.6...
mass is constant and
w is 2pi x (6.6...)

Answer 32

w = 2*pi*f = 2*pi*6.6x10^15
r = 5.3x10-11
m = you knw it


F = m w^2 R

Answer 33

http://www.wolframalpha.com/input/?i=w+%3D+2*pi*6.6x10%5E15%2C+r+%3D+5.3*10-11%2C+m%3D9.10938291*10%5E%28-31%29%2C+m*w%5E2*r+%3D+%3F

Answer 34

okay thank you

Answer 35

np :)

Answer 36

i am getting an answer of 8.30 x10^-8

Answer 37

wolfram says 65794 ?

Answer 38

i dont know what i am doing wrong, I keep getting that answer

Answer 39

lay back... relax and work it again after some time :)

Answer 40

w = 2 pi (6.6x10^15) = 4.146 x 10 ^16

f = (9.1 x 10^-31) (5.3 x 10^-11) (4.146 x 10 ^16)^2 = 8.3 x 10^-8

Answer 41

i am putting ( ) around everything and it still doesnt work...i dont think wolf.. is correct ?

Answer 42

someone else got the same answer as me too =(

Answer 43

Oh ya ! you're right !!!
ive plugged it incorrectly.

here is the correct link :-
http://www.wolframalpha.com/input/?i=w+%3D+2*pi*6.6*10%5E15%2C+r+%3D+5.3*10%5E%28-11%29%2C+m%3D9.10938291*10%5E%28-31%29%2C+m*w%5E2*r+%3D+%3F

Answer 44

omg thank you, i thought i was going insanee

Answer 45

good you're alert enough to catch my mistake =))

Answer 46

thanks =)

Answer 47

np :D