Home work 2

Write due date here_____________________

Your name ___________________________

Your answers and figures should be contained in a file (preferrably Word) to be submitted electronically via the link below.

 

The following problems are for you to practice problem solving and idea generation. These designs should pass the “conceptual test”, i.e., after seeing the drawings, the reader can agree prototypes based on these designs will possibly work. A good design should be able to solve at least one anticipated problem.

 

1.-        Provide a design of a sensing mechanism that can measure the speed of a bicycle. Detailed drawings that illustrate the concepts are essential. Anticipate one possible practical problem and provide a second design (based on the first one, or completely different) that overcomes the problem.

2.-        Provide a design of a system for lining-up screws on an assembly-line conveyor belt so that they are all pointing in the same direction. Detailed drawings that illustrate the concepts are essential. Anticipate one possible practical problem and provide a second design (based on the first one, or completely different) that overcomes the problem.

3.-        You are given an egg, some tape, and several drinking straws. Using only these materials, design a system that will prevent the egg from crashing when dropped from a height of six feet (two meters). Detailed drawings that illustrate the concepts are essential. Explain what natural element or phenomena you are trying to use to your advantage.

 

Logbook and Record Keeping:

 

4.-        When calculations are performed, the answers will only be as accurate as the weakest link in the chain. An answer should be expressed with the same number of significant figures as the least accurate factor in the computation. Express the result of each of the following computation with an appropriate number of significant figures:

1.      V=(12.9 mA) (1500 Ω)

2.      F=2.69 kg x 9.8 m/s2

3.      F=-3.41 N/mm x 6.34 mm

4.      iB=(1.29 mA)/(100)

5.      Q=(6.891 x 10-12 F)(2.34 x 103 V)

 

Estimation: start from some available data, use simple operations to obtain yourself estimates of quantities that might be very useful in an engineering design. See for yourself how powerful this tool is. The goal is not to find these estimates as an information but to calculate them, 75% of credit will be given to shown calculations.

 

5.-        Estimate the cost of leaving your computer running 24 hours a day. The only data you need to find from the internet, if you haven’t done so, are the cost of 1kWh, and the power consumed by a computer (usually shown in the technical descriptions)

6.-        Estimate the number of bricks in an average-sized house chimney. Draw sketches for the brick and the chimney, show YOUR estimate for the dimensions of each (you may see an actual brick on campus and get a good estimate of its size), then give the number of bricks according to those estimates

 

Spreadsheet: Excel

 

7.-        Download the xls file by clicking here here.  Use this file to calculate the average (formula: “=average(firstcell:lastcell)”) and standard deviation (the real standard deviation, formula: “=stdev(firstcell:lastcell)”), for each of the five columns. List the ten numeric results (average and standard deviation for each of the 5 columns in that file). Please be careful about this order and manipulations in Excel, since the answers will be graded as right or wrong.

 

_____     ______    ______    ______     ______    ______    ______    ______   ______   _______      _______

 

 

The following questions are from LabVIEW

 

8.-        You’re in the Block Diagram window inside LabVIEW, wiring an operator and a string indicator. You’ve wired circuits before and they worked, so you are an experienced ‘wirer’, but this time you always get a broken wire. What could have happened and how do you fix the problem?

 

9.-        You’re having a broken  Run Button, tell two ways to get the error list

 

10.-      Tell how would you assign the connectors of a newly designed subVI.

 

 

Before you submit the your electronic file: make sure  (i) it is named hw2_lastnameplusinitial;  (ii) it has been compressed and is less than 70K in size. If it is not possible to reduce the file size under that limit, you should submit via email attachment to the instructor’s address or using a disk . Late homework due to submission technical problems will not be accepted. Click here to submit your file.