1.

A light rod of length 1 m is pivoted at its center and two masses of 5 kg and 2 kg are hung from the ends as shown in the figure. Find the initial angular acceleration of the rod assuming that it was horizontal in the beginning. ?

Answer»

GIVEN in the question :-


Length l = 1 m

Mass m₁ = 2 kg

m₂ = 5 kg.

Now we know the formula


F₁ r₁ - F₂r₂ = m₁r₁² + m₂r₂²


Hence,

I = 2 * 0.5^2+ 5 * 0.5^2

I = 7 × 0.25

I =1.75 kg.meter².


Torque about the PIVOT, i.e T = m₁r₁ + m₂r₂

T = 5 × 0.5 - 2 × 0.5

T = (1.5 × g) Nm


Therefore the ACCELERATION


\alpha = \frac{T}{I}

α = (1.5 × g) / 1.75

α = (1.5 × 9.8)/ 1.75

α = 14.7 / 1.75

α = 8.4 rad/second²




Hope it Helps :-)



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