Question

Two blocks of masses 2 kg and 4 kg are hanging with the help of massless string passing over an ideal pulleyinside an elevator. The elevator is moving upward with an accelerationg/2.The tension in the string connectedbetween the blocks will be (Take g = 10 m/s2).

(1) 40 N
(2) 60 N
(3) 80 N
(4) 20 N​

Answer 1

Attachment of the question figure

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✴ Two blocks of masses 2 kg and 4 kg are hanging with the help of mass less string passing over an ideal pulley inside an elevator. The elevator is moving upward with an accelerating/2.The tension in the string connectedbetween the blocks will be (Take g = 10 m/s2).

(1) 40 N

(2) 60 N

(3) 80 N

(4) 20 N

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➡ Option. A ) 40N

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Given :-

• Two blocks of masses 2 kg and 4 kg are hanging with the help of mass less string passing over an ideal pulley inside an elevator.

• The elevator is moving upward with an accelerating/2.

To Find :-

• The tension in the string connectedbetween the blocks.

Calculation :-

For 4 kg of block ,

➡ 4g - T + 4g/2 = 4a

➡ 6g - T = 4a..........(1)

For 2 kg of block ,

➡ T - 2g - 2g/2 = 2a

➡ T - 3g = 2a.......(2)

Multiplying by 2,

➡ T - 3g = 2a.......(2) × 2

➡ 2T - 6g = 4a....... (3)

Subtracting , 1 - 3

➡6g - T - ( 2T - 6g ) = 4a - 4a

➡ 6g - T - 2T + 6g = 0

➡ 12g - 3T = 0

➡ 3T = 12g

➡ T = 12g/3

Taking, g = 10 m/s²

➡ T = 12× 10/3

➡ T = 120/3

➡ T = 40N

✏ The tension in the string connectedbetween the blocks is 40 N.

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