Explore BrainMass
Share

Mechanical Engineering

Energy Analysis Of Closed Piston Systems

A mass of 15 kg of air in a piston-cylinder device is heated from 25 to 77 degrees Celsius by passing current through a resistance heater inside the cylinder. The pressure inside the cylinder is held constant at 300 kPa during the process, and a heat loss of 1.0 kJ occurs. Determine the electric energy supplied, in kWh. Answ

Energy Analysis Of Closed Systems

A 4 x 5 x 7 m room is heated by the radiator of a steam heating system. The steam radiator transfer heat at a rate of .... Please show all work step by step and include all applicable formulas. (See attached file for full problem description)

Energy Analysis or a Closed System Piston

Hydrogen is contained in a piston-cylinder device at 14.7 psia and 15 ft3. At this state , a linear spring (F x) witha spring constant of 15,000 lbf/ft is touching the piston but exerts no force on it. The cross-sectional area of the piston is 3 ft2. Heat is transferred to the hydrogen, causing it to expand until its volume dou

Determining the exit velocity from an air nozzle

Air enters a nozzle operating at steady state at 800 ºR with a negligible velocity and exits the nozzle at 570 ºR. Heat transfer occurs from the air to the surroundings at a rate of 10 Btu per pound of air flowing. Assuming ideal gas behavior and neglecting potential energy effects, determine the velocity at the exit in ft/s.

Steam Enters a Turbine Operating at Steady-State

Steam enters a turbine operating at steady-state at 700 ºF and 600 lbf/in2 and leaves at 0.6 lbf/in2 with a quality of 90%. The turbine develops 12,000 hp, and heat transfer from the turbine to the surroundings occurs at a rate of 2.5x106 Btu/h. Neglecting kinetic and potential energy changes from inlet to exit, determine the

Refrigerant R-134a vapor in a piston-cylinder assembly

Refrigerant R-134a vapor in a piston-cylinder assembly undergoes a constant-pressure process from saturated vapor at 800 kPa to 50 ºC. For the refrigerant, determine the work and the heat transfer, per unit mass (each in kJ/kg). Changes in kinetic and potential energy are negligible.

A piston-cylinder device initially contains 50L

A piston-cylinder device initially contains 50L of liquid water at 40 degrees C and 200kPa. Heat is transferred to the water at constant pressure until entire liquid is vaporized. (a) What is the mass of the water? (b) What is the final temperature? (c) Determine total enthalpy change. (d) Show process on a T-v diagram with

Buoy Problem - Center of Gravity

(See attached file for full problem description) A cylindrical buoy two meters in diameter and six meters high is floating upright in seawater as shown at 20 degrees C. The buoy contains weather recording instrumentation and has a mass of 12,000 kg. Its center o gravity is 2 meters above the bottom. a) Determine the depth

Psychrometry

Please solve the problem using an atmospheric pressure of 85 kPa. Do not use a psychrometric chart but from first principles using formulae. I think you need to use steam tables: In an air-conditioning unit 3.5 m^3/s of air at 27 degrees Celsius dry-bulb temperature, 50% relative humidity and standard atmospheric pressure enter

Length of stroke, cylinder bore, clearance volume, thermal efficiency

The four cylinders of a four-stroke spark-ignition petrol engine have a total capacity (swept volume) of 1200 cm^3. The stroke-bore ratio is 1.1, the compression ratio is 9.5 and the ratio of the specific heats (y) is 1.41. Determine: (a) the length of stroke (b) the cylinder bore (c) the clearance volume per cylinder

Power transmission velocity

(See attached file for full problem description) A four car linkage is shown in the attachment. The crank OA, the connecting rod AB, and the rocker BC are 20mm, 120mm, and 60mm long respectively. The crank rotates at a speed of 60 rpm and the centre distance OC is 90mm. At the instant shown determine: (I) The velocity of C

Components and Force of a Timber and a Wall

A timber of uniform cross section with a mass of 90 kg is hinged at its lower end and held at angle of 60 degrees with the horizontal by a rod attached as shown in (attached figure 4-6) A cylinder which has a mass of 30 kg is placed between the timber and the wall. 1) What are the horizontal and vertical components of the r

Centrifugal force question

In the speed-regulator system of the attached diagram, it has a mass of 1 kg. The frequency needed to maintain the configurations shown in the diagram is calculated as 6.145 rad/s. Calculate the centrifugal force of the system. a. 0.577 N b. 0.230 N c. 0.410 N d. 0.313 N

Frequency Calculation from L and C

For the circuit shown, the capacitance has a value of 50 microfarad. Calculate the value of inductance L that will make the oscillation occur at the frequency of 400HZ. a. 0.0127 H b. 0.0032 H c. 0.002 H d. 0.0045 (See circuit diagram in attached file).

Output-input amplitude

(See attached file for full problem description) Consider the attached transfer-function system. Solve for the output-input amplitude ratio given the sinusoidal input.

Combined Resistance Between Two Points

The resistors R1, R2, and R3 are connected in a triangular shape as shown. Obtain the combined resistance between point A and B. (See attached file for full problem description).

Spring-mass system problem

For a spring-mass system the spring constant is 245 N/m and the mass is 22 kg. The natural frequency of this system is: a. 2.1 rad/s b. 2.6 rad/s c. 3.34 rad/s d. 5.2 rad/s

Bullet and Wood Block Problem

A bullet is fired horizontally into a wood block resting on a horizontal, frictionless surface. If the mass of the bullet is 0.02 Kg and the velocity is 600 m/s, what is the velocity of the wood block after the bullet is embedded in it? Assume the wood block has a mass of 50 kg. a. 1 m/s b. 2 m/s c. 2.5 m/s d. 0.24 m/s

Time & Distance Before a Car Stops

A brake is applied to a car traveling at a constant speed of 25 m/s. If the deceleration caused by the braking action is 5 m/per second squared, find the time before the car stops. a. 1s b. 2s c. 4s d. 5s Determine the distance traveled before the car stops, IF the car stops at t = 5 seconds. a. 52.5 m b. 62.5 m c. 25

Kinetic Energy & Stopping Force of a Car

A car of mass 1500 kg is moving with a speed of 50 km/h (13.89 m/s). Determine the kinetic energy T of the car. (see options a through d in attached file) Now determine the force required to stop the car at a distance of 50 m, if the kinetic energy T is 1.447 x 10E5 N-m. 10E5 means 10 to the 5th power. a. 1447 N b. 289

Determining Time to Reach Maximum Height

A ball with a mass of 0.25 kg is thrown vertically upward with an initial velocity of 10 m/s. What is the velocity of the ball when it reaches the highest point? a. 10 m/s b. 0.25 m/s c. 0 m/s d. Can not be determined How many seconds would it take for the ball to reach its maximum height. a. 10s b. 1.02 s c. 0.25 s d