Question

Find the unknown mass of the block 1 needed to balance the bar. Assume that the mass of the bar is negligible. Block 1 is located 0.85 m left of the center of the bar. Blocks 2 and 3 are located at 0.25 m and 0.50 m right of the center of the bar. The masses of the blocks 2 and 3 are showed. Give the result in the nearest whole number. Do not include units in the result. Use the gravity acceleration on Earth, g = 10 m/s2

Answer 1

Answer:

Incomplete question: The masses of the blocks m₂ = 1.5 kg and m₃ = 2 kg

Explanation:

Given data:

L₁ = length = 0.85 m

L₂ = 0.25 m

L₃ = 0.5 m

m₂ = 1.5 kg

m₃ = 2 kg

Question: Find the unknown mass of the block 1 needed to balance the bar, m₁ = ?

The torque is zero (intermediate point of the bar)

$-m_{1} gL_{1} +m_{2} gL_{2} +m_{3} gL_{3} =0$

Is negative because mass 1 is to the left of the coordinate system (see the diagram)

$m_{1} =\frac{m_{2} gL_{2}+m_{3} gL_{3} }{L_{1} } =\frac{(1.5*0.25)+(2*0.5)}{0.85} =1.6176kg$