Explore BrainMass

Mechanical Engineering

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

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^

Thermodynamic Equilibrium

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

Assignment Question 3 in Applied Mechanics

Fig. Q3 shows a rigid light beam which is hinged at O to a wall. The beam carries a point mass of m at the free end. The beam is connected at its mid-point to a spring (stiffness k) which is also connected to a support that moves with a vertical motion y = Y sinwt. A damper (coefficient c) connects the mid-point of the beam to a

Finding Vertical Distance in Pipe Line System

For the system in attachment, calculate the vertical distance between the surfaces of the two reservoirs when water at 10 degrees celcius flows from A to B at the rate of 0.03 m^3/s. Both pipes are cast iron and the elbows are standard. The total length of the 3" pipe is 100 meters. For the 6" pipe, it is 300 meters.

Automobile Pump Power

Gasoline is pumped from the gas tank of an automobile to the carburetor through a 10 ft long, 1/4" diameter fuel line of steel tubing. The line has five 90 degree smooth bends with r/d of 6. The gasoline discharges through a 1/32" diameter jet in the carburetor to a pressure of 14 psia. The pressure in the tank is 14.7 psia.

Dynamics Problem

In the pulley system shown, object "A" moves downwards with a velocity of 3m/s. Determine the magnitude and direction of the velocity of object "B".

NC Programming Created

Create an nc part program for making the slot shown in the attachment.The cutter diameter is 3/16 inch. The starting point is (0,0) at 2 inches to the left and 2 inches below the lower left corner of the part. There is also an example with a fully worked out solution included in the attachments. Write also the apt geometry and


2) See attachment for diagrams for both questions. 1) Two water manometers are connected to a tank of air. One leg of the manometer is open to 100kPa absolute pressure while the other leg is subjected to 90kPa. Find the difference in deflection between both manometers, delta ha - delta hb. 2) The inclined differential

Beam deflection and Stress at centroid?

Sometimes the term centroid throws me for a loop. So, how would I set this problem up? I'm asked to determine the deflection of the tip of a beam and max direct stress and location for a 2000N load. Given load=2000N, on the tip of a 1m beam. Beam dimensions are H=80mm B=W=40mm and t=thickness of 1.5mm.

Determine modal ratios

For the two degrees of freedom structure shown, what are the values of the modal ratios if m1 = m2 = m, k1 = k, and k2 = 3k See Attached for question and details.

Determine Viscous Damping Coefficient C

A Mass-Spring-Damper is tested to determine the value of the viscous damping coefficient c. Assume k = 10 lb/ft and m = 2 slug. The vibrational amplitude is observed to decrease by 33% of its initial value after two consecutive cycles. What is the value of the viscous damping coefficient c? a. 0.9376 b. 0.8442 c. 0.779

Find the fuel consumption

In the an ideal turbo jet, the engine is designed such that the turbine work is divided equally between the compressor and the propeller. The gas from the turbine discharges to a nozzle for additional thrust. Consider such an engine where the air enters the diffuser at 200 m/s, 40 kPa, 240 K, and a flow rate of 40 kg/s. The comp

Question about Multipal choice question on mechanics

A car with a mass of 2,000. kilograms is moving around a circular curve at a uniform velocity of 25 meters per second. The curve has a radius of 80 meters. What is the centripetal force on the car? a. 625 N b. 703N c. 15,625 N d. 20,250 N

Brayton Cycle Gas Turbines

Large stationary brayton cycly gas turbine power plant delivers a powr output of 100MW to an electric generator . Minimum temperature is 300K so T1= 300k max temp is 1600k so T3= 1600k Minimum pressure in the cycle is 100kpa compressor pressure ratio is 14 to 1 so p2/p1 = 14 but turbine efficiency is 85% and compressor efficienc

Mobility and transit time

Consider the 2.0micrometer long GaAs device where the E-field is 5kV/cm and Mn*=.067M0. (a) Calculate the transit time of an electron through the device if the mobility is 8000 cm^2V-s. (b) The mean free path of an electron (average velocity x scattering time) is the average distance an electron travels between two consecu

Excess carrier concentrations and diffusion current density.

Consider a bar of p-Si that is homogeneously doped to a value of 3x10^15 at T=300K. The applied electric field is zero. A light source is incident on the end of the semiconductor. The excess-carrier concentration generated at x=0 is deltap(0)=deltan(0)=10^13/cm^3. Neglect surface effects. Mun=1200/cm^2/Vs. Mup=400/cm^2/Vs.

Quasi Fermi Level

Q. An n-type silicon sample with Nd=10^16cm-3 is steadily illuminated such that g'=10^21cm-s^-1. If tn0=tp0=10^-6s, calculate the position of the quasi-Fermi levels for electrons and holes with respect to the intrinsic level (assume that ni=1.5x10^10cm^-3).

Barrage Energy Example

The area of morecambe bar at high water is approx. 200km^2. At low water most of the bay is exposed sand. for this exercise, we could assume that on average the sand slopes evenly so that half way between high and low tide the area of water is 100km^2. The tidal range (between low and high tide) varies between 4m at neap tide

Difficulty over a problem relating to the motion of a projectile.

A player throws a ball with an initial velocity Vo of 15 m/s from a point A located 1.5 m above the floor. Knowing that the ceiling of the gymnasium is 6 m high, determine the highest point B at which the ball can strike the wall 18 m away. This problem was taken from the curvilinear motion of particles inside the kinematics

Representative velocity profiles

Womersly’s Problem: Plot some representative velocity profiles for the purely oscillatory flow of a Newtonian fluid in a long, rigid, straight pipe at various phases of the flow (3-4). For these plots, use the values of constants given below: Constants: Velocity (u): 105 cm/s Diamter (d): 2.23 cm Kinematic viscosit

Rankine Cycles

Consider an ideal steam reheat and regenerative cycle where steam leaves a steam gen and enters a high pressure turbine at 3 Mpa and T=400 C and is extracted to an open feedwater heater at 0.8 Mpa. The remainder is reheated to 400 C at this pressure which flows to the low pressure turbine stage. The condenser saturation pressure

Diesel engine

A diesel engine has air before compression at 280 K and 85 Kpa. The highest temperature is 2219 K and the highest pressure is 6 MPa. Find the volumetric compression ratio and the mean effective pressure using cold air properties at 300K.