Chronology | Current Month | Current Thread | Current Date |
[Year List] [Month List (current year)] | [Date Index] [Thread Index] | [Thread Prev] [Thread Next] | [Date Prev] [Date Next] |
Leigh is of course correct. Explicitly:components
Define
A = angle of elevation of the line joining the (equal masses);
T1, T2 = angles from the vertical of the two strings.
F(el) = the electrical coulomb force magnitude.
Then
T1*sinT1 = T2*sinT2 (cuz each side = F(el) *cosA.)
T1*cosT1 = T2*cosT2 (cuz each side = mg)
Dividing:
tanT1 = tanT2; QED
This only fails if the masses are unequal.
Bob
Bob Sciamanda (W3NLV)
Physics, Edinboro Univ of PA (em)
trebor@velocity.net
http://www.velocity.net/~trebor
----- Original Message -----
From: Leigh Palmer <palmer@SFU.CA>
To: <PHYS-L@lists.nau.edu>
Sent: Friday, September 10, 1999 4:45 PM
Subject: Re: Electrostatics problem
Leigh: Newton's 3rd law is part of translational equilibrium in this
case. This alone doesn't make the angles the same.
The gravitational force is entirely vertical. The horizontal
Theof the tension forces must, therefore, be equal to the horizontal
components of the electrostatic forces and oppositely directed (they
equilibrate the horizontal components of the electrostatic forces).
equalstrings have the same lengths, so the only way the horizontal
components of forces which must lie along the strings can be made
vertical.is by making the strings make equal angles with respect to the
Leigh