Question 31. A two-wheel drive tractor weighing 21 kN has a wheel base of 2.1 m. The CG of the tractor is 0.7 m ahead of rear axle centre. The tractor is pulling a single-axle trailer with gross trailer weight of 50 kN on a leveled concrete road while maintaining the line of pull parallel to the ground surface. The tractor hitch point is
42 cm behind the rear axle centre and 52.5 cm above the ground surface. During operation, 20% of the gross trailer weight is transferred to the tractor hitch point. If the coefficient of rolling resistance for each of the tractor and trailer wheels is taken as 0.04, and their ground reactions are assumed to pass through their respective wheel centres, the dynamic ground reaction against the tractor rear wheels in kN is

Question 32. In an experimental setup, the discharge through a triangular notch is 0.0074 m3 s-1 at an operating head of 0.1 m. The coefficient of discharge for the notch is 0.7. If the required discharge is 0.1 m3 s-1 the corresponding width of water surface in m is

Question 33. A two-wheel drive tractor weighing 21 kN has a wheel base of 2.1 m. The CG of the tractor is 0.7 m ahead of rear axle centre. The tractor is pulling a single-axle trailer with gross trailer weight of 50 kN on a leveled concrete road while maintaining the line of pull parallel to the ground surface. The tractor hitch point is
42 cm behind the rear axle centre and 52.5 cm above the ground surface. During operation, 20% of the gross trailer weight is transferred to the tractor hitch point. If the coefficient of rolling resistance for each of the tractor and trailer wheels is taken as 0.04, and their ground reactions are assumed to pass through their respective wheel centres, the gross traction ratio developed by the tractor is

Question 34. Specific heat capacity of dry air and water vapour are 1.005 and 1.88 kJ kg-1 K-1, respectively. In an energy conserving system, 1 kg s-1 air at 300C with constant absolute humidity of 0.02 kg water (kg dry air)-1 is heated up to 650C. Water at the wet bulb temperature of air is then sprayed into the air so that the final temperature of the air-water vapour mixture is 400C. Latent heat of vapourization of water at 700C and 400C are 2334 and 2407 kJ kg-1, respectively. The absolute humidity of the exhaust air from the spray chamber in kg water (kg dry air)-1 is

Question 35. A tractor mounted off-set type reciprocating mower is driven by the PTO shaft. The maximum inertia force of 3.2 kN occurs along the pitman at 320 crank angle and 270 pitman angle with the horizontal plane. The knives of the cutterbar are riveted to the slider. If each of the allowable tensile and compressive stresses of the slider material is 50 MPa, the minimum cross-sectional area of the slider in mm2 is

Question 36. A piston pump is driven by a 5 m diameter horizontal axis wind turbine for supplying water from a borehole with a total pump head of 10 m. The mean velocity of air is 18 km h-1 and the density of air is 1.29 kg m-3. The actual power coefficient of the wind turbine is 0.30 and the overall pump efficiency is 60%. Neglecting the transmission losses, the expected pump discharge in L s-1 will be

Question 37. A 4-cylinder, 4-stroke compression ignition engine has piston stroke of 10.5 cm and cylinder bore of 11 cm. At a mean piston speed of 7 m s-1, the developed brake mean effective pressure is 650 kPa. The brake power in kW developed by the engine is

Question 38. A centrifugal pump having an overall efficiency of 75% requires 6 kW power at 1450 rpm to deliver water against a suction head of 5 m and a delivery head of 12 m. If the pump runs at 1650 rpm and frictional head losses are negligible, the total head developed by the pump in metres will be

Question 39. The flywheel of a hand operated chaff cutter with two cutting knives is rotated at 30 rpm and is connected to a worm gear assembly for driving the feed rollers. The number of teeth of the worm gear is 24 and number of starts (threads) of the worm is 2. If diameter of each of the feed rollers is 15 cm, the chaff length in mm will be

Question 40. A diesel engine running in dual fuel mode with diesel as pilot fuel and producer gas as primary fuel produces 3.5 kW at rated engine speed and is coupled directly to a generator for producing electricity. The amount of diesel and producer gas consumed per hour is 460 ml and 12.5 m3, respectively. Assuming calorific value of diesel and producer gas as 35280 and 3.97 MJ m-3, respectively, the brake thermal efficiency of the engine in percentage is