ASSIGNMENT NO. -2

SUBJECT: MEC 201 (MECHANICS OF SOLIDS) TYPE: NUMERICALD O A: D O S: PART A

Q-1 The plastic 50mm-diameter is placed in a 51 mm diameter hole with rigid

walls. Determine the change in length of the rod after the 8-kN load is

applied. Use E= 40 MPa and ν= 0.45 for the rod.

Q-2. The lower ends of the three vertical steel bars were at the same level the

homogeneous, rigid block of weight W was attached. The cross-sectional

areas of the bars at A and C are 1.0 cm2. Determine the cross-sectional

area of the bar at B so that the axial force in each bar is W/3.(Replace all

dimention by 1ft =10cm in figure.)

Q-3. A timber column, 8cm. by 8 cm. in cross section, is reinforced on all four

sides by steel plates, each plate being 6 cm. wide and t in. thick. Determine the

smallest value of t for which the column can support an axial load of 300N if the

working stresses are 12 N/mm2 for timber and 100N/mm2 for steel. The moduli of

elasticity are 50 GPa for timber and 200 GPa for steel .

PART B

Q-4 The steel shaft is formed by attaching hollow shaft to a solid shaft.

Determine the maximum torque T that can be applied to the ends of the

shaft without exceeding a shear stress of 70 MPa or an angle of twist of

2.50 in the 3.5m length. Us G= 83GPa for steel.

Q-5 A flexible shaft consisting of a 0.20m diameter steel rod encased in a

stationary tube that fits closely enough to impose a torque of intensity

50N/m. on the rod. (a) Determine the maximum length of the shaft if the

shear stress in the rod is not to exceed 50 MPa. (b) What will be the relative

angular rotation between the ends of the rod? Use 200 GPa for steel.

Q6. A 40 mm diameter hole is drilled 3 m deep into the steel shaft. When the two

torque are applied, determine (a) the maximum shear stress in the shaft:

and (b)the angle of rotation of the free end of the shaft. Use G= 83 GPa for

steel.