Step 1: Calculate the MTBF You decide to run a test to determine the mean time between failures. During the test, you start with 10 operational machines on your production line producing widgets. You record breakdowns during a 100- hour observation period in which two of the machines broke down. One at 35 hours into the test and the other at 50 hours into the test. Use Excel and the data you collected to calculate the MTBF of your machines. Step 2: Calculate the Expected Breakdown Maintenance Costs After collecting and analyzing the MTBF data you were surprised at how often your machines really broke down. At your last company you remember that they had a service firm that would come in and perform preventive maintenance (PM) on your machines and you wonder if this would be an option to reduce breakdowns. However, before you go to your boss to pitch the idea you want to see if using an outside PM firm would reduce your cost. So you do some research on the cost and run another study on the number of breakdowns of your machines. You run the study for one year and create a chart containing the number of breakdowns and the number of months that breakdowns occurred. Number of Breakdowns Number of Months that Breakdowns Occurred 0 0 1 9 2 7 3 5 You also do some research on breakdown cost and find that the average cost of a breakdown to your firm is $350. You find a service firm and request a price quote from them. The PM service firm costs $200 per month, but they tell you that you can still expect on average of 2 breakdowns per month even with the PM service. Use Excel and the data to calculate the expected breakdown maintenance cost versus hiring the PM firm to service your machines.

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.

answer: b 56, 250

explanation:

a

b

b

a

c

b

d

d

none of these are correct, as they are all sources of american law

a

what is the actual question i have no idea how to answer this w/o a question