Question

a block mass 0.2kg is suspended from the ceiling by a light string . a second block of mass 0.3 kg is suspended from the first block through another string. find tention in two string.

Answer 1

weight of block 1 ,w=mg
w=0.2 × 9.81 = 1.962 N
weight of block 2,w =0.3×9.81 =2.943 N

tension in lower string =1.962 N
tension in upper string=1.962+2.943= 4.905N

Answer 2

Required Solution :

Here we're having two blocks first one is of 0.2 kg and second of 0.3 kg. Second block is attached to the first block by a string and the first block is suspended (or attached) to the ceiling through a string.

(Both the blocks are applying Gravitational force and the tension force) .

• First block is applying Gravitational force towards the centre of earth and a tension force in upward direction. (Towards the ceiling)

• Similarly, second block is even applying the Gravitational force towards the centre of earth and a tension force in upward direction.(Towards the first block).

★ For 1st block :

Here, T2 would even be added to first force (Gravitation) according to free body diagram.

→ Gravitational force (F₁) + T₂ = T₁

→ mg + T₂ = T₁

→ 0.2 × 10 + T₂ = T₁

→ 2 + T₂ = T₁

★ For 2nd block :

Here, according to free body diagram :

→ T₂ = F₂

→ T₂ = mg

→ T₂ = 0.3 × 10

→ T₂ = 3N

★ Substituting the value of T₂ :

→ T₁ = 2 + 3

→ T₁ = 5N

Therefore,

• Tensions in the two strings are of 3N & 5N respectively.