Explore BrainMass

Mechanical Engineering

Determining Shape Factor: Thermal Conductivity and Heat Loss

A thin disk is maintained at 75 degrees celsius and placed on the surface of a large medium maintained at 10 deg C. The thermal conductivity of the medium is 1.4 W/m-deg C, and there is a heat loss of 36 W. The shape factor, S is closest to: a) 20 cm b) 40 cm c) 60 cm d) 80 cm

Determine heat flow and thermal resistances

Heat flow through a uniform wall will: a) increase as the thermal resistance increases b) increase as the thickness of the wall increases c) decrease as the thermal differences on each side of the wall increases d) decrease as the thermal resistance increases

Determine Fourier Number

Compare two identical steel spheres, except the first has a two inch diameter while the second sphere has a four inch diameter. The larger sphere will have a Fourier number approximately: a) half that of the smaller sphere b) four times larger than that of the smaller sphere c) twenty-five percent of the value of

Find the closest ambient temperature

A fireclay brick cube, 10 cm in length is removed from a furnace where it was maintained at a temperature of 500 degrees C. The brick cube is then placed in ambient temperature conditions. The heat flow from the brick is 400 Watts. The closest ambient temperature is: a) 300 deg C. b) 200 deg C. c) 100 deg C. d) 0 d

Tire Explosion Prediction Math Model

You witnessed the failure of a nylon rim which exploded injuring the person filling the tire with air. Develop a documented mathematical model that predicts the time required to reach a specific pressure. Your results are to be tabulated and plotted. Specifically predict the time to change from 100 kPa to 800 kPa. Assume the pro

Tensile test results

From the test results: Draw load vs extension graph Determine modulus of elasticity Determine the 0.1% proof stress

Metlab Functions: Two Row Vectors as Inputs

Write a Matlab function that will accept two row vectors (A and B) as inputs. The function computes the row vector C that is the term-by- term product of A and B (that is, C1= A1*B1, C2=A2*B2, and so on), and that then computes the values of the function sin(x) for each value of C and stores these values in the row vector D. The

Determine the Radius of Curvature

For the composite bar indicated (see attachment), determine the radius of curvature caused by the couple of moment 70 Nm. a) 9.16 mm b) 12.73 mm c) 11.87 mm d) 10.41 mm

Determine Stress on a Given Beam

For the beam in the attachment, determine the stress at point D located 32mm below point A. a) 18.6 MPa b) -15.8 MPa c) 19.2 MPa d) 18.1 MPa

Maximum Normal Stress Due to Bending

For the beam illustrated (see attachment), determine the dimension b for which the maximum normal stress due to bending is 40 MPa. a) 7.45 mm b) 8.95 mm c) 8.33 mm d) 9.36 mm

Largest Bending Moment

For the beam shown (see attachment), determine the largest bending moment that can be applied without exceeding either of the following allowable normal stresses: +7 ksi and -12 ksi.

Kinetics of Particles and Newton's Second Law

Determine the maximum theoretical speed that may be achieved over a distance of 50 m by a car starting from rest, knowing that the coefficient of static friction is 0.80 between the tires and the pavement. Assume four-wheel drive. In answering this problem, how can you use the coefficient of friction without mass?

Determine Stress

Knowing that the couple shown acts in a vertical plane, determine the stress at (a)point A. (b) point B.

Finding Metal Removal Rate

In an electrochemical machining operation, the frontal working area of the electrode is 2.5in squared. The applied current=1500amps, and the voltage=12volts. The material being cut is pure aluminum, whose specific removal rate is 1.26 x 10^-4 in^3/amp-min. If the electrochemical machining process is 90 percent efficent, det

DB - Find the capacity of a cylindrical tank

1. Find the capacity of a cylindrical tank that is 250 feet in diameter and 30 feet high? 2. In the above problem, what is the capacity if the tank is 75% full, and what is the capacity in gallons? 3. If 50 pounds of chlorine are mix with 100 pounds of water, what is per cent chlorine solution that is made? 4. Find

Calculating Modulus of Rupture

See the attached wood block diagrams. If a break load of 250 lbs. is applied to the first wood specimen, how do I determine the Moment of Inertia and calculate the Modulus of Rupture? The only difference between the specimens per the attached diagram is that a 1/4" x 1/4" key-way is cut into the center of the 2nd specimen.

Future Value of sums of money over eight years

Your rich godfather has offered you a choice of one of the three following alternatives: $10,000 now; $2,000 a year for eight yeaers; or $24,000 at the end of eight years. assuming you could earn 11 percent annually, which alterantive should you coose? If you could earn 12 percent annually, would you still choose the same altera

Saturated vapor at pressure in rigid tank

A 1.8m^3 rigid tank contains steam at 220C. One third of the volume is in the liquid phase and the rest is in the vapor form. Determine: A) The pressure of the steam B) The quality of the saturated mixture C) the density of the mixture

Freebody Diagrams Problem

Draw a freebody diagram of the support pole AO for the awning and add the forces acting upon the pole.

Freebody Diagrams Problem

Draw a freebody diagram of a bar AB as well as the forces that are acting upon that bar. Use the attached file.

Finding tangent and cosine

Find the expressions (in terms of a and b) for cosine theta and tangent theta. Use the picture attached. See attached file for full problem description.

Pre-heating of combustion air?

250 psi saturated steam at approximately 400 degrees F is used to pre-heat ambient air at 60 degrees F through a 100% theoretically efficient heat exchanger. The desire is to raise the temperature of the ambient air from 60 degree F to 350 degrees F ---- I need to calculate the amount of steam energy in BTU's per minutes and

Design Air Mass Flow Required

Water enter a cooling tower at 400C and drops 150C of temperature before exit. The tower receives atmospheric air at 200C and 40% relative humidity. The air leaves the tower at 350C and 95% relative humidity. If the atmospheric pressure is 1.01325 bar determine the design air mass flow required to handle 12,000 litres/min of co