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zorro
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Homework Statement
In the given figure, all the springs and pulley are ideal and surface is frictionless. The rod is massless. The time period of horizontal oscillations of the block is?
The Attempt at a Solution
I used two different approaches and both give different and wrong answers-
Consider a very small rotation of the rod by an angle θ. Let x be the displacement of the mass m.
1) Torque-
Trestoring = -(k/4*2*(lθ)*l + k(2lθ)*2l)
Simplfiying and writing L.H.S as 4ml2α
α = -9k/8m*θ
ω2 = 9k/8m
2) Force-
Frestoring = -(k*2lθ + k/4*2*lθ) = -5klθ/2 = -5kx/4
a=-5kx/4m
ω2 = 5k/4m
Can someone point out any mistake above and show me the correct method?