Fwd: eLearning Lesson 1 and 2 by Christopher Nah (19)

Lesson 1

Question 1

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Question 2

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Lesson 2

I will be showing 5 examples of real life applications of mechanisms (Levers, Linkages, gears, etc) either at home, playground, etc and explain how the mechanisms are being used effectively.

1) <Refer to picture 3>

http://farm3.static.flickr.com/2197/2212013077_dc3cf83637.jpg

The above picture shows a pair of scissors. It is a lever and is being used effectively as the sharp blade focuses the pressure exerted by the hands onto a smaller area so that it is easier and more effective to cut something this way.

2)<Refer to picture 4>

http://i00.i.aliimg.com/photo/v1/318125826/soft_closing_cabinet_door_hinge.jpg

The above picture shows a door hinge. It is a system that comprises of springs (for retraction of door) and linkages. It is being used effectively as the linkages limit the door to a certain limit of movement (To prevent unnecessary injuries) and also the spring that helps to retract the door when closing to reduce the total amount of effort needed by the user to exert.

3) <Refer to picture 5>

http://www.cartuningpoint.com/wp-content/uploads/2009/07/coil-spring.jpg

The above picture shows a car spring. It is a spring mechanism and is being used effectively to reduce shaking (Shock absorber) in the car when it goes over obstacles or road humps. It also contributes to the car's handling and breaking for safety in driving

4) <Refer to picture 6>

http://thumbs.dreamstime.com/thumblarge_534/1283239174Nd0Z7l.jpg

The above picture shows a car gearbox system. It is a system that comprises of multiple gears for the drivers to switch gears when necessary. It is being used effectively as when the car needs to go up a steep slope, the driver can switch to a smaller gear for a bigger gear ratio, such that the driver needs to turn more rounds than the driven and this contributes to the total amount of "power" the car has to move up the slope.

5) <Refer to picture 7>

http://www.personal.psu.edu/jlw1086/wheel_n_axle.jpg

The above picture shows a car steering system. It is a wheel and axle mechanism and is being used effectively by allowing the driver to use lesser effort to turn the steering wheel by letting the circumference of the wheel be a lot more than the axle's circumference. This thus makes the driver have more handling of the car and contributes to road safety. It also have "holes" in the steering wheel such that the driver can grab the wheel effectively and turn it smoothly. It also thus contributes to overall road safety.

The identified problematic situation: 

<Refer to picture 8>

The above picture shows a portable fan (Ignore the table) that can be rotated vertically to change the angle that the fan blows. Although a useful and nice portable fan, I think there are some problems and the design can be improved. 

Firstly, the fan would have an awkward centre of gravity and thus would be easy to flip over. 

Secondly, the angle of rotation allowed for the fan to move (to me) is too wide and when rotated the wrong direction, would get the wire tangled. 

Thirdly, the wire will get tangled as it is mounted at the back of the fan. I think it might be better to mount it at the base.

<Refer to picture 9>

Sorry for being late.. Had some difficulties..

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Thanks!

Yours sincerely,
Christopher Nah