- #1
PsychonautQQ
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- 10
Homework Statement
A uniform rod with a length of 10 meters and a mass of 20 kilograms has a 20 kilogram mass on one end and a 40 kilogram mass on the other end. Where should the fulcrum be located for this beam to balance?
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| V |
|20kg| |40Kg|
Homework Equations
Torque = Force * Radius
The Attempt at a Solution
Usually when i did problems like this I'm pretty sure the board was considered mass-less, and I'm not sure how to do it now that it has mass. Is calculus needed?
Anyway, let's consider:
20 kg mass = m1 @ r1
40 Kg mass = m2 @ r2
and then to figure in the boards mass can we just consider it to have a center of mass on each side (that obviously depends on where the fulcrum is)?
if so...
Left side of board = m3 @ r3
right side of board = m4 @ r4
(m1g*r1) + (m3g*r3) - (m2g*r2) - (m4g*r4)=0
m1g + m2g + m3g + m4g = Normal force of fulcrum
Anyway I'm a little stuck obviously ..