Explore BrainMass

Mechanical Engineering

Manufacturing Processes

Please answer the following questions: Certain manufacturing processes have the following characteristics described below. Please characterize the process in terms of : Type of process, state of workpiece material and the type of process energy used. 1. A metal is cast into a mold and solidifies 2. A metal bar is reduce

Mechanical Vibration Analysis

For this two degree fo freedom model, how do I find the matrix equation of motion? How do I find the value of the modal ratios if m1=m2=m, k1=k and k2=3k? If a force of 25sin3t is applied to m2, how do I find the value of the response if m1=m2=1 slug, k1=10lb/ft and k2=30lb/ft?

Mechanical Vibration Analysis

In this idealized model, m=1 slug, k=9lb/ft, and the viscous damping factor is 0.15. How do I find the range of frequency ratios for which the magnification will be greater than 1? How do I find the forced response for A=1, and forcing frequency of 4rad/sec?

Mechanical Vibration Analysis

How do you find the equation of motion for an idealized model? For this model how do you find the periodic time (time in sec) and the natural frequency (rad/sec)? Please see attached for diagram.

Turbomachinery and Reaction Turbines

1) Steam at 15 bar and 350 degrees C is expanded through a 50% reaction turbine to a pressure of 0.14 bar. The stage efficiency is 80% for each stage and the reheat factor is 1.05. The expansion is to be carried out in 10 stages and the required power is 6000 kW. Calculate the steam flow required, assuming that the stages all de

Turbomachinery: Reaction Turbines

Please help with the following problem. Sketch the fully annotated velocity triangles for a Parsons turbine stage. Use your sketch to show that the specific work produced per stage is given as w_stage = (C_b)^2 [1 + 2(f/C_b)(cot(B_1))]. At a particular stage of a Parsons reaction turbine, the mean blade speed is 60 m/s an

Turbomachinery: Impulse Turbine

1) The steam from the nozzles of a single wheel impulse turbine discharges with a velocity of 600 m/s at an angle of 20 degrees. The blade wheel rotates at 3000 rev/min and the mean blade radius is 590 mm. The axial velocity of the stream at the exit from the blades is 164 m/s and the blades are symmetrical. Sketch the annota

Mass Moment of Inertia and Translational Motion

1. Calculate the mass moment of inertia about the x axis. The total mass of the object is 13 kg. 2. The plate with two holes is made of steel with a density of 7800 kg-m3. The radius of each hole is 5 cm. Determine its mass moment of inertia about the z-axis. 3. Determine the mass moment of inertia about the y axis. The t

Moment of Inertia and Translational Motion

1. A four-wheel truck that has a mass of 5,000 kg accelerates forward. The coefficient of friction for the front and back wheels is 0.2 and 0.4, respectively. What is the acceleration of the truck? Assume that the friction force on both the front and rear wheels are at a maximum and both are about to slip. 2. Each of the 2 b

Turbomachinery: Impulse and Reaction Turbines

1. An impulse air turbine rotor with a blade speed (U) of 300 m/s is measured to have a relative rotor inlet velocity (W_1) of 750 m/s at an angle of 69 degrees and an outlet relative velocity (W_2) of 660 m/s. Th temperature and pressure in the rotor are 375 K, 0.83 bar. Calculate the rotor efficiency, rotational speed and powe

Calculating the Second Moment of Area

It is necessary to design a square-section composite bar that will withstand an applied load without deflecting more than a specified amount.The design specification for the bar, including its dimensions and loading criteria, is given below. Using the formula below, calculate the second moment of area of the bar and use this

Solve for Force (Engineering Dynamics)

Two forces act on a slender bar that is pinned at (see attachment). The horizontal reaction at 0 is 5 lb to the right, the force F in lb is closes to which answer choise? a) 25 b) 30 c) 15 d) 27 *Please see attachment for equations and diagram

Dynamics Problem - Backspin (Friction, Velocity)

A 1.2ft diameter ball is thrown onto a rough surface, such that it has a velocity of 6ft/s and a backspin angular velocity of w. If it is to stop backspinning at the same instant as the velocity is 0, the backspin w in rad/s is what? HINT: The answer is independent of the mass and coefficient of friction. a. 17.8 b. 22.0 c. 2

Dynamics Problem - Tangential Acceleration an Velocity

A board rides on two driving drums. At the instant shown (*see attached), the board has the acceleration noted. If the board is not slipping on the drums and the total acceleration of the drum contact points is 3m/s[squared], the velocity in m/s of the board at this instant is closest to which answer choice? a. 0.8 b. 0.9 c

Calculating maximum velocity, displacement and stretch

The pair of blocks, which are connected by a cord, are released from rest when the spring is unstretched. The static and kinetic coefficients of friction are .2 and .1, respectively. The following things are to be found using the work-energy methods: 1) Maximum Velocity of the blocks 2) Stretch of the spring at the maximu

Thermodynamics Problem: Heat Pump

Hi, I am confused about how to answer the following question. Any assistance would be appreciated. Question: A heat pump with a COP (coefficient of performance) of 2.8 is used to heat an air-tight house. When running, the heat pump consumes 5 kW of power. If the temperature in the house is 7 degrees Celsius when the heat pum

Combustion Reactions: Thermochemistry

1. The analysis by mass of a sample of petrol was 85.5% C and 14.5% H2. Calculate the stoichiometric A/F ratio. Also determine the actual A/F ratios and the dry analyses for mixture strengths of 90% and 120%. 2. Find the stoichiometric A/F ratio (by mass) for the combustion of benzene (C6H6). Compute the actual A/F ratio and do

Angular Impulse Force

Assuming an angular impulse =0.5*3(25/12)=3.125pound*ft*sec and an impact that takes 0.1 second, with what force (in pounds force) will the door strike the door jamb? Please provide an explanation with the equations, arithmetic calculations and units.

Pressure Cooker and Mass Flow Rate

Steam is leaving a pressure cooker whose operating pressure is 30 psi. It is observed that the amount of liquid in the cooker has decreased by 0.4 gal in 45 minutes after the steady operating conditions are established, and the cross-sectional area of the exit opening is 0.15 in^2. Determine (a) the mass flow rate of the steam a

Calculating a Constant Pressure Process

In a constant pressure, nonflow process, 6Btus of heat are added to a gas while the volumes change from 1.6ft^3 to 2.0ft^3. If the temperature decreases by 10*F and the system contains 2 lbm of gas, find the pressure in the system. (Cv=.2Btu/lbm*F) 1Btu=778 ft-lbm

Rate of Evaporation

Water is to be boiled at sea level in a 30-cm-diameter stainless steel pan placed on top of a 3-kW electric burner. If 60% of the heat generated by the burner is transferred to the water during boiling, determine the rate of evaporation of water. See Figure 2-39 attached. Please show steps.Thanks.

Superheated Water Vapour

Superheated water vapour at 180 psia and 500 degrees Farenheit is allowed to cool at a constant volume until the temperature drops to 250 degrees Farenheit. At the final state, determine: (a) the pressure (b) the quality (c) the enthalpy. Also, show the process on a T-v diagram with respect to saturation lines.

Boundary Layer Theory and Turbulent Flow in Pipes.

a) Calculate the power required to overcome the skin friction drag on the keel of a sailing dingy moving through water at 2m/s. The keel projects 0.8m into the water and it is 0.4m wide. Assume that the keel is a smooth flat rectangular plate and that transition from laminar to turbulent flow occurs instantaneously at Re = 4*10^

Graphs for Static Force Systems

1) An object of weight 20kn is supported from above by two cables, inclined at 40 degrees and 70 degrees to the horizontal. Find graphically the tensions in the cables. 2) Find graphically the forces f1 and f2 in the crane. The triangle is standing up with a 90 degree angle next to the wall on top, with f1 pointing towards

Thermodynamic Equilibrium

For a system to be in thermodynamic equilibrium, do the temperature and the pressure have to be the same everywhere? Explain.