Mechanical Engineering Answers

i do not know how to determine the units of coefficent A. i have been given a formula: v(t) = A (1-e ^ - t/tmaxspeed), t is time in seconds, tmaxspeed is time to reach maximum speed in seconds and A is constant. i have been given the information that t (0-28 m/s) is 2.8s, t (400m) is 10.91s & tmaxspeed is 7.0s. I also have to identify the physical meaning of A; velocity of the car at t=0; derive an equation a(t) for the instantaneous acceleration of the car as a function of time? And then Identify the acceleration of the car at t = 0s and asymptote of this function as t → ∞?

Air and fuel enter a furnace used for home heating. The air has an enthalpy of 320 kJ/kg and the fuel has an enthalpy of 43027 kJ/kg. The gases leaving the furnace has an enthalpy of 616 kJ/kg. There are 17 kgair/kgfuel, water circulated through the wall furnace receiving heat. The hose required 17.02 kW of heat, what is the fuel consumption per day. (41 kg/day)

what courses you can answer Q for ?
I have subjects like numerical analysis (matlab stuff ) , fluid mechanics , vibration , design of mechanical elements , engineering management .
can you answer Q for these subjects

A finned plate is to be constructed of aluminum and designed to dissipate 125 W to a surrounding room with air at 20◦C. The base for the fins is to consist of a flat vertical plate with multiple straight vertical fins having a rectangular profile. The base plate thickness must not exceed 3 mm, and the heat source on the back side of the plate is a power device that must operate at a temperature below 75◦C. For the design, you are to determine a suitable set of the following parameters that will accomplish the heat transfer objective: (1) width and height of base plate, (2) number of vertical fins and spacing, (3) length and thickness of fins, and (4) surface treatment (if any) to enhance radiation heat transfer from the fins.

The exhaust gas leaving an oil engine is passed through a heat exchanger which
consist of tubes surrounding by water. The gas enters at 327 oC and leaves at 193
oC. The water enters the exchanger at 17 and leaves at 56 oC. If the mass flow rate
of water is 2.54kg/min. Determine the mass flow rate of gas, take cp of the gas is
1.04 kJ/kg.

Calculate the internal energy and the enthalpy of 1 kg of air occupying 0.05 m3
at
20 oC at 20 bar. If the internal energy is increased by 120 kJ as the air compressed
to 50 bar. Calculate the new volume occupied by 1 kg of air.

6.Thin pieces of 0.3mm-thick hot-rolled strips of 1080 steel are heat-treated in the following ways:(a) Heat for 1 h at 860°C; water-quench. (b) Heat for 1 h al 860°C; water-quench; reheat for I h at 350°C. What is the name of this heat treatment? (c) Heat for 1 h at 860°C; quench in molten salt bath at 700°C and hold for 2 h; water quench. d) Heat for 1 h at 860°C; quench in molten salt bath at 260°C and hold for 1 min; air-cool. What is the name of this heat treatment? (e) Heat for 1 h at 860°C; quench in molten salt bath at 350°C: hold for 1 h: air-cool. What is the name of this heat treatment? (f) Heat for 1 h at 860oC; water-quench; reheat for 1 h at 700°C. Use the IT diagram below and other knowledge to determine the microstructure of the steel samples after each heat treatment. Note that there are other questions stated between (a) and (f), where relevant, and must be answered as well.

2. Draw a typical isothermal transformation diagram for plain carbon eutectoid steel and indicate the various decomposition products expected by simple diagrammatic drawing (5)
3. Explain how you would use a series of experiments to construct the diagram in question 2? (8)
4. Draw time-temperature cooling paths for a 1080 steel on an Isothermal transformation diagram that will produce the following microstructures. Start with the steels in the austenitic condition at time = 0 and 850ooC. (a) 100% martensite, (b) 50% martensite and 50% coarse pearlite, (c) 100% fine pearlite, (d) 50% martensite and 50% upper bainite, (e) 100% upper bainite, and (f) I00% lower bainite. (8)

When a certain perfect gas is heated at constant pressure from 15 oC to 95 oC, the
heat required is 1136 kJ. While when the same gas is heated at constant volume
between the same temperature limit above the heat required is 808 kJ. Calculate
cp,cv,

, R and molecular weight of the gas.

Air at 200kPa, 30°C is contained in a cylinder behind a piston with initial volume of 0.1 m3. The inside pressure balance ambient pressure of 100 kPa plus an external imposed force that proportional to V3, Now heat is transfer to the systēm to final pressure of 225 kPa. Find the work done for this process