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**pendulum!! help!!**

## Homework Statement

A pendulum 2 meters long with a mass of 1kg is mounted on a circular platform on the earth's surface that's spinning at constant angular velocity. The pendulum is mounted on a pole that's perpendicular to the platform at a distance of 5 meters from the center of rotation. The equilibrium angle the pendulum makes with the pole is 30 degrees.

**1) What's the angular velocity at equilirium?**

2) If it's displaced for its equilibrium position, what will be the period of the pendulum?

2) If it's displaced for its equilibrium position, what will be the period of the pendulum?

## Homework Equations

a=F/m

a=v2/r

F=mv2/r

http://answerboard.cramster.com/Answer-Board/Image/cramster-equation-2007422035166331114291678125006410.gif [Broken]

P.S. My physics teacher said that the diagrams below explains what's happening:

FROM A BIRD'S EYE VIEW-

http://answerboard.cramster.com/Answer-Board/Image/200743163856633112151365000000302.jpg [Broken]

FROM A NORMAL VIEW-

http://answerboard.cramster.com/Answer-Board/Image/2007431724446331121788484375005079.jpg [Broken]

## The Attempt at a Solution

1) R=5+r1

R=5+1= 6

h= l(1-Cos θ)

= 2(1-Cos 30degrees)

= .2679

http://answerboard.cramster.com/Answer-Board/Image/cramster-equation-20074317292633112181428593750754.gif [Broken]

v=

*2.29 m/sec*ω=V/r

ω =2.29/1=

*2.29 rad/sec*2) Now, my teacher said something along the lines of that I have to replace the acceleration due to gravity (g) in the period equation with an acceleration. Ergo, the equation would appear like this: http://answerboard.cramster.com/Answer-Board/Image/cramster-equation-2007431735306331121853068750002401.gif [Broken].[/URL] Now I know that it doesn't seem right, but take in mind that the circular platform is moving, not the pendulum its self.

So,

__:__

**I am not sure which acceleration I should use since I somehow have 3**1)F=mv2/r a=f/m

F=1(2.29)2/6= .874 N a=.

**874 m/sec2**

2)a1: Sin θ= opposite/hyp.

Sin 30degrees(9.8)=

**4.9 m/sec2**

3)a2: Cos θ=adjacent/hyp.

Cos 30degrees(9.8)=

**8.49 m/sec2**

**Do I even use an acceleration in place of g or just use g??**

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