Mechanical Engineering Answers

Suppose you have a 1020 steel plate in axial loading, with an axial F of 30000 lbf.  The plate is 1⁄4” thick, 2” high, and 6” length. The hole is in the center of the  plate, and is 1/4“ in diameter. The plate is at room temperature, and the strain at  fracture is greater than εf > 0.1. If Sy = 80 ksi and Sut = 100 ksi, calculate the highest  stress in the plate.

A body having a cylindrical shape of length equals to 1.9 m and diameter equals to 400 mm is inside a room where the ambient temperature is equal to 300 K. The initial temperature of the body is equal to 350 K. If the heat convective coefficient is equal to 1.3 W/m^2.K. What condition should the thermal conductivity k verify in order to apply the lumped capacitance method

3. Determine the intensity of shear of an oil having viscosity =1 poise. The oil is used for lubricating the clearance between a shaft of diameter 10cm and its journal bearing. The clearance is 1.5 mm and the shaft rotates at 150 r.p.m

The thrust of the XLR99 rocket engine was essentially constant at 57,000 lb during the powered phase of the X-15 flight. For the maximum altitude flight on August 22,1963, the aerodynamic drag at the burnout altitude of 176,000 ft was only 252 lb, due to very low air density at that altitude. The empty weight of the X-15 was 14,590 lb. Using the equation of rate of climb l, which contains the assumption of steady unaccelerated flight, calculate the rate if climb of the X-15

a nozzle is supplied with steam having a specific enthalpy of 3268kj/kg, specific volume of 0.4m^3/kg and velocity of 10m/s. at exit of the nozzle, the specific volume and specific enthalpy of the steam are 1.32m^3/kg and 3072kj/kg, respectively while losing heat at rate of 25kw . for an inlet area of 800cm^2, determine : 1.the mass rate flow

2.the exit velocity

3.the change in kinetic energy

4.exit volume flow rate

an insulated cylinder device contains 2kg of water as expands at a constant pressure of 175 kpa. the initial volume and specific enthalpy of the water are 0.5m^3 and 485kJ/kg, respectively. the water is stirred by a paddle wheel amounting work transfer of 400 kJ while a current of 8A flows for 45min through a resistor placed in the water. if the final specific volume and specific enthalpy are 1.25m^3/kg and 1594 kJ/kg,respectively; determine 1.the boundary work done

2.the voltage of the source

At a dairy farm milk flows through a 22mm diameter pipe at an average velocity of 0.25m/s

p=1028kg/m^3 , u=3.0*10^-3 Pa.s

1) what is the volumetric flow rate in L/s

2) Determine whether the flow in the pipe is laminar or turbulent.support your answer.

3)Futhure along the pipe , the pipe dismeter reduces to 15mm. For the reduced section,determine whether the flow regime has remained the same as in (2) or has changed . Support your answers

A hot air balloon consists of a gonodola(the basket within in which people sit or stand) and the envelope (the actual balloon filled with hot air). When fully inflated with hot air,the envelope has a volume of 2800(metre cubed). Assume that the nylon skin of the envelope,gondola, burner and propane tanks to heat the air have a combined mass 300kg

If the hot air balloon is secured to the ground with a rope and ground peg and the air inside the fully inflated envelope is heated to 70°, p=1.028kg/m^3, determine the tension in the anchor rope if the ambient air temperature is 10°C, p=1.246kg/m^3

In a pin jointed four bar mechanism ABCD, the lengths of various links are as follows:

A B = 25 mm ; BC = 87.5 mm ; CD = 50 mm and AD = 80 mm. The link AD is fixed and the angle BAD = 135°. If the velocity of B is 1.8 m/s in the clockwise direction, find 1. velocity and acceleration of the mid point of BC, and 2. angular velocity and angular acceleration of link CB and C

A square (a×a) in a plan, has a height L and a relatively of 0.8. What would be a permissible a/L limit so that the cylinder may float in stable equilibrium with its axis vertical?