Question

Two blocks are connected by an ideal cord that does not stretch, the cord passes over an ideal pulley. The weight of the heavier block is 1.2 N larger than the weight of the lighter block. The lighter block has the acceleration 4.4 m/s2 up. What is the weight of the heavier block?

Answer 1

Gravitational acceleration = g = 9.81 m/s

Mass of the lighter block = m₁

Mass of the heavier block = m₂

Tension in the cord = T

Acceleration of the blocks = a = 4.4 m/s²

The weight of the heavier block is 1.2 N larger than the weight of the lighter block.

(m₂ - m₁)g = 1.2 N

m₂ - m₁ = 0.1223

From the free body diagram,

T - m₁g = m₁a

T = m₁g + m₁a

m₂g - T = m₂a

m₂g - m₁g - m₁a = m₂a

(m₂ - m₁)g = (m₁ + m₂)a

(m₁ + m₂)(4.4) = 1.2

m₁ + m₂ = 0.2727

m₂ - m₁ = 0.1223

Adding these two equations we get,

2m₂ = 0.395

m₂ = 0.1975 kg

Weight of the heavier block = m₂g = (0.1975)(9.81) = 1.937 N