Mechanical Engineering Answers

In a epicyclic gear train an arm carries two gears A and B having 40 and 60 teeth. If arm rotates at 200 rpm in clockwise direction about the centre of gear A which is fixed makes 300 rpm in the anticlockwise direction, what will be the speed of gear B.

6. A closed container contains 2 kg of fluid on a given datum. The container is now raised

vertically 1000m and the fluid is given a velocity of 50 m/s. The work done ON the fluid is 50 kJ

and the heat added is 30 kJ. If the initial internal energy is U 1 = 20 kJ, find U 2 .

A piston-cylinder containing steam at 700 kPaa and 250 o C undergoes a constant pressure process until the quality is 70%. Determine per kilogram.

A bakery oven is constructed of refractory material having an

average thermal conductivity of 0.8 Btu/hr-ft-F. The inside dimension

of the oven are 7’ x 6’ x 2’. If the wall of the oven is 4.5 in. thick and

the temperature of the inner and outer surfaces are 1200F and 200 F,

respectively, what is the total heat loss per day in the oven wall?

A hollow sphere with 4 in. inside diameter and 12 in. outside 

diameter has an inner surface temperature of 500 F and outer 

surface temperature if 300 F. If the thermal conductivity of the 

sphere material is 25 Btu/hr-ft-F, what is the rate of heat flow?

A hollow sphere of pure iron contains a liquid chemical

mixture which releases 1,000,000 Btu/hr. If the inside diameter

and the outside of the sphere is 0.5 ft. and 1 ft., respectively,

determine the inner surface temperature of the sphere assuming

the outside surface temperature is 100 F.

A 6-in. nominal diameter mild steel pipe (OD=6.625 in.) has an inside

surface temperature of 500 F. The pipe is covered with a 3 in. layer

of 85 percent magnesia insulation which has a surface temperature

of 100 F. Determine the heat loss in Btu/hr-100 ft of pipe.

k for magnesia = 0.043Btu/hr-ft-F

k for steel = 28.2

Estimate the heat transfer loss on a chimney having 12 cm inside

diameter insulated by 6 cm refractory cement. The inside and outside

temperature are 200 C and 30, respectively. If the chimney is 20 ft.

long, what is the total heat loss by conduction on the wall. Assume

k=0.138 kcal/hr-m-C.

The wall of the rice hull furnace is made up of 9 in. of fire

brick (k=0.72 Btu/hr-ft℉), 5in.of insulating brick (k=0.08

Btu/hr-ft-F)and 7.5 in. of red brick (k=0.5 Btu/hr-ft-F) . The

inner and outer surface temperatures 𝑡1 and 𝑡4 are 1500℉

and 150℉, respectively. Neglecting the resistances of the

mortar joints, compute the temperatures 𝑡2 and 𝑡3 at the

contact surface.

A rice hull furnace is to be designed to consume rice hull

at a rate of 5 sack/hour (10 kg/sack). If the furnace has an

outside dimension of 1 m wide x 1.5 m long x 1.2 m high,

what is the percentage heat loss by conduction from the

wall of the furnace? The wall is insulated by 8 in. thick brick

material. Inside and outside temperature are 400℃ and

40℃ , respectively.