Q-1 A motor car shaft consists of a steel tube 30 mm internal diameter and 4 mm thick. The engine develops 10 kW at 2000 r.p.m. Find the maximum shear stress in the tube when the power is transmitted through a 4 : 1 gearing. Q-2 A line shaft rotating at 200 r.p.m. is to transmit 20 kW. The allowable shear stress for the material of the shaft is 42 MPa. If the shaft carries a central load of 900 N and is simply supported by bearing 3 meter apart, determine the diameter of the shaft. The maximum tensile or compressive stress is not to exceed 56 MPa. Two plates 16 mm thick are joined by a double riveted lap joint. The pitch of each row of rivets is 90 mm. The rivets are 25 mm in diameter. The permissible stresses are as follows: ot = 140 MPa; t = 110 MPa and oc = 240 MPa Find the efficiency of the joint. Q-3 Q-4 A single riveted double cover butt joint is made in 10 mm thick plates with 20 mm diameter rivets with a pitch of 60 mm. Calculate the efficiency of the joint, if ot = 100 MPa ; t = 80 MPa and oc = 160 MPa. Q-5 A double riveted double cover butt joint is made in 12 mm thick plates with 18 mm diameter rivets. Find the efficiency of the joint for a pitch of 80 mm, if ot = 115 MPa ; t = 80 MPa and oc= 160 MPa.