Mechanical Engineering Answers

A PIR motion detector made with an infrared faceted fresnel lens has the following properties:

• Focal length of single facet lens = 22.5 mm
• Distance of object from lens = 12.5 m
• Minimum displacement of object which results in detection = 250 mm
• Number of facets = 8

What is the facet pitch in mm?

How should I estimate uncertainty by the GUM (Guide to the expression of uncertainty) method for an indirect solar dryer?

The turning moment diagram of an engine which has been drawn to scale of 1mm to 56Nm and 1mm to 1° of rotation of the crankshaft shows the greatest amount of energy which jas to be stored by the flywheel is represented by an area of 3500mm2. The flywheel is to run at a mean speed of 350 rmp with a total speed variation of 2.5%. If the mass of the flywheel is to be 585kg, determine suitable dimensions for the rim, the internal diameter being 0.85 of the external diameter , neglect the inertia of the arms and hub of the flywheel. Cast iron has a density of 7.2Mg/m3

Consider a Boeing 747 flying at a standard altitude of 36,000 ft. The pressure at a point on the wing is 400 lb/ft2. Assuming isentropic flow over the wing, calculate the temperature at this point

Listed below are varying combinations of stresses acting at a point and referred to axes x and y in an elastic material. Using Mohr's circle of stresses, determine the principal stresses at the point and their directions for each combination. or (N/mm or mm Try (N/mm +5 (i) +54 +30 (ii) +30 +54 +5 36 (iii) -60 (iv) +30 +30 50 om at 11.50 to x axis 29 N/mm (i) ou +55 N/mm Ans. on at 11.5 tox axis (i) on +55 N/mm OIL (iii) on 34.5 N/mm om 61 N/mm ay at 79.5° to x axis. (iv) on --40 N/mm on 60 N/mm2 on at 18.5 to x axis

Find a household material wherein you can demonstrate Poisson's Ratio and provide a short video clip wherein the change in longitudinal and lateral dimensions can be shown.

A perfect rectangular prism is on top of a beam. The beam has two supports on each corner. The cross section of the beam is a circle (d = 7.05 cm).

Solid Steel box: length = 1.45 m , weight = 9000 N.

Length of beam = 1.45 m

What is the max normal compressive stress on the beam?

A double acting steam engine runs at 210 rpm. A curve of turning moment plotted on the crank angle base showed the following areas alternatively above and below the mean turning moment line: 880,500,620,720,360,560,440,520mm²

The scales used where 1mm= 520Nm and 1mm= 1^o crank angle. If the total fluctuation in speed is limited to 1.85% of the ,mean speed, determine the mass of flywheel necessary if the radius gyration is 1.4m

An ideal Brayton-cycle gas turbine with regeneration but no reheat or intercoolingoperates at full load with an inlet temperature to the compressor of 60oF and an inlet temperature to the turbine of 1540oF. The cycle is also to be operated at part load at a pressure ratio of 3.0 with a turbine inlet temperature of 1100o F. Compare the thermal efficiency and network output per lbm flow for the two operating points if the working fluid (air) is treated as a perfect gas and the maximum possible regeneration is obtained.

1. You are a design engineer working for a natural gas transmission company. You are assigned to a design team that is charged with preparing the proposal to the state Public Utility Commission to build a plant to receive liquefied natural gas from oceangoing tankers and unload it into your company’s gas transmission system. What technical issues and societal issues will your team have to deal with?

2. Brazil is rapidly developing into one of the world’s most dynamic economies. As a country it is blessed with great mineral resources, abundant unused farm land, and network of free flowing rivers. But, to achieve its potential, it will need a much expanded transportation network and considerably expanded electric generation capacity. Much of this expansion will occur in the undeveloped center of the country including the Amazon region. Define the major obstacles to large-scale development and suggest the best technologies to achieve it.

3. List three products that are made from a single component.

4. Differentiate the capabilities of CAD/CAM/CAE in a tabular format

5. Perform a literature search and/or a web search in the history of CAD/CAM

6. What is 2 ½ D model? Sketch some examples. Also please write when this method is preferred.

7. CAD/CAM is an interdisciplinary field. Many academic scientific journals are available. Now, could you make list of available journals, magazines and newsletters in CAD, CAM, CAE

8. Make a list of popular product ideas that could attract the Indian users

9. Starting from the need, write a note on the life cycle of a common product that you use regularly. (Omit the technical details that are beyond your comprehension)

10. List the different disciplines/branches of engineering the combined efforts of which result in the successful design and development of some commonly used products/services. Relate them to the components

11. What are all main hazards related to oil and gas industry?

12. What are the benefits of occupational safety and health management system?