Question

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 m. The upper wire has negligible mass and the lower wire has a uniform mass of 0.2 kg/m. The whole system of blocks, wires and support have an upward acceleration of 0.2 m/s² . The acceleration due to gravity is g = 9.8 m/s²

Answer 1

(a) 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

T₁ - 2.0g = (2.0) a

or T₁ =(2.0)(g + a) = (2. 0)(9.8 + 0.2) = 20 N

(b) 50N

Answer 2

Answer is (a) 20N, (b) 50N