- #1

TA1068

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## Homework Statement

A horizontal uniform bar of mass m and length L is hung horizontally on two vertical strings. String 1 is attached to the end of the bar and string 2 is attached a distance L/4 from the other end. A monkey of mass m/2 walks from one end of the bar to the other. Find the tension T_1 in string 1 at the moment that the monkey is halfway between the ends of the bar.

## Homework Equations

[tex]\tau = rFsin\theta[/tex]

[tex]F_thrust = ma_t = mr\alpha[/tex]

## The Attempt at a Solution

In all honesty, I'm really not too sure where to start.

I drew a diagram of what is going on. I know at least that the tensions are going to add up to (3/2)mg, since there is the m of the bar pulling down and also the m/2 of the monkey pulling down and the system is in equilibrium.

So: [tex]T_1 + T_2 = 1.5mg[/tex]

Becomes: [tex]T_1 = 1.5mg - T_2[/tex]

Do I have to choose a pivot point? I was thinking where [tex]T_2[/tex] connects to the bar, because it was an answer to a question leading up to this, but I'm not exactly sure why? What effect does placing the pivot point here have in relation to [tex]T_2[/tex]?

Any help would be greatly appreciated!