Two blocks of mass 2.9 kg and 1.9 kg are suspended from a rigid support S by two inextensible wires each of length 1 meter, see fig. The upper wire has negligible mass and the lower wire has a uniform mass of `0.2kg//m`. The whole system of blocks wires and support have an upward acceleration of `0.2m//s^2`. Acceleration due to gravity is `9.8m//s^2`.

(i) Find the tension at the mid-point of the lower wire.
(ii) Find the tension at the mid-point of the upper wire.

Answer

543

Explanation

To find tension at mid-point of the lower wire we cut the string at this point draw the free body diagram of lower portion.
The equation of motion gives `T_(1) -2.0g =(2.0)a`
or `T_(1) =(2.0) (g +a) = (2.0) (9.8 + 0.2) =20N`
(ii) To find tension at mid point of upper wire The equation of motion gives
`T_(2) -5g =5a` Therefor
`T_(2) =5 (g + a) =5 (9.8 + 0.2) = 50N`

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