- #1

- 78

- 0

V(tangential) = 2pi R / T

i'm not sure if 33.33 rev/min is the V, but i tried plugging in the respective numbers and solve for R, didnt really make much sense.

You are using an out of date browser. It may not display this or other websites correctly.

You should upgrade or use an alternative browser.

You should upgrade or use an alternative browser.

- Thread starter huskydc
- Start date

- #1

- 78

- 0

V(tangential) = 2pi R / T

i'm not sure if 33.33 rev/min is the V, but i tried plugging in the respective numbers and solve for R, didnt really make much sense.

- #2

Pyrrhus

Homework Helper

- 2,179

- 1

- #3

- 78

- 0

and i have :

f = ma

N=mg

from that i solve for a, which = .8829

but i'm still confused as to what that 33.333 rev/min

- #4

Pyrrhus

Homework Helper

- 2,179

- 1

That's just the speed.

It's simply:

[tex] F_{friction} = m \frac{v^2}{R} [/tex]

It's simply:

[tex] F_{friction} = m \frac{v^2}{R} [/tex]

- #5

- 78

- 0

i tried:

F = m (v^2/R)

like you said, V = 33.333

mu g = (v^2 / R) and solve for R this way, didn't work. i've been told that 33.333 is not just V. and if it is, then what's the T for?

- #6

Pyrrhus

Homework Helper

- 2,179

- 1

You need to have common units!, convert rev/min to m/s!

Last edited:

- #7

- 78

- 0

converted rev/min to rad/s.

i did this:

33.333 rev / min x (1 min/60 sec) x (2pi rad/ 1 rev) = 3.49 rad/s

with mu g = (v^2 / R) , R= (v^2)/mu g

am i doing something wrong that i just don't see?

- #8

Pyrrhus

Homework Helper

- 2,179

- 1

Is that how the book states it, it looks to me you would need to use.

[tex] F_{frictionn} = m \frac{4 \pi^{2} R}{T^{2}} [/tex]

where T is the time for one revolution or the period T, but what you did above, should have worked just the same.

- #9

- 78

- 0

Thanks so much!!! (physics is so hard....well for me it is...)

- #10

Pyrrhus

Homework Helper

- 2,179

- 1

it came from

[tex] v = \frac{2 \pi R}{T} [/tex]

substitute in

[tex] a_{c} = \frac{v^2}{R} = \frac{4 \pi^{2} R}{T^2} [/tex]

Share: