The Coffee Shop around the Corner (CS) is famous for its fresh-made muffins. Hank, the owner of CS, knows that the demand for muffins depends very much on the time of the day: The demand is high in the morning decreases in the afternoon hours and is at its lowest in the evening. Hank is having trouble deciding how many muffins to make for each period of the day. He asked you to help him forecast the demand. If you do a good job in forecasting the demand for tomorrow, Hank will pay you to do this job on a recurring basis. The following is the demand data Hank collected in the past three days: Day 1 2 3
Period Morning Afternoon Evening Morning Afternoon Evening Morning Afternoon Evening
Demand 37 25 9 48 28 14 53 33 17
Using a 5-period moving average, forecast the morning, afternoon and evening demand for muffins on day 4.

The Coffee Shop around the Corner (CS)

5-period Moving Average Forecast of Demand

Day 4        Based on Average   Educated Guess

Morning            29.8                       41

Afternoon         29.8                       30

Evening            30.8                        19

Explanation:

a) Data and Calculations:

Day 1           Demand    5-period Moving

                                           Average

Morning           37

Afternoon       25

Evening            9

Day 2

Morning         48

Afternoon      28                     29.4

Evening          14                     24.8

Day 3

Morning        53                     30.4

Afternoon     33                     35.2

Evening         17                     29.0

Day 4

Morning                                29.8

Afternoon                             29.8

Evening                                30.8

b) Given that for the past three days, coffee demand in the evenings had not exceeded 20, we can tweak the evening demand to less than 20 and carry the remainder to the morning when demand is always high.  In that case, the demand on day 4 may read more like, Morning 41, Afternoon 30, and Evening 19.

sound is invisible, but sometimes we can feel it. when a kettle-drum is thumped with a stick that time the tight drum skin moving up and down very quickly for some time and then it pumped sound waves into the air. loudspeakers also work in a similar manner.

components of a speaker:

electromagnet

in order to translate an electrical signal into an audible sound, an electromagnet is used in looudspeakers

  suspension

suspension is used to   center the voice coil in the gap of the magnet and it exerts a restoring force to keep it there. suspension is used to limits the maximum mechanical excursion of the diaphragm and voice coil.

voice coil

voice coil is a coil of wire which is attached to the apex of a loudspeaker cone. it provides the motive force to the cone by the reaction of a magnetic field to the current passing through it.

cone

in a   loudspeaker, a   thin, semi-rigid membrane attached to the voice coil, which moves in a magnetic gap due to which it vibrates   and produced sound. it is known as diaphragm and it can also be called a cone, though not all speaker diaphragms are cone-shaped.

surround

surround is also known as front suspension. surround is used to join the cone to the chassis. together with the suspension it controls the cone excursion, and it is also used to   determine how energy which is   travelling through the cone is absorbed, and how the speaker limits when it reaches the ends of its travel.

dustcap

dustcap is used to protect the voice coil from dust and dirt. it is a part of the cone.

how speaker work

the outer part of the cone is fastened to the outer part of the loudspeaker's circular metal rim. the inner part is fixed to   voice coil that sits just in front of a permanent magnet . when loudspeaker is hooked up to a stereo, electrical signals feed through the speaker cables into the coil. it will convert the coil into an electromagnet magnet . when electricity flows back and forth in the cables, the electromagnet either repels or attract the permanent magnet. this moves the coil back and forth, and it pull and push the loudspeaker cone. like a drum skin vibrating back and forth, the moving cone pumps sounds out into the air.in this way loudspeakers works.