Afan is designed to last for a certain time before it will have to be replaced (planned obsolescence). the fan only has one speed (at a maximum of 700 rpm), and it reaches the speed in 5.0 s (starting from rest). it takes the fan 7.0 s for the blade to stop once it is turned off. the manufacturer specifies that the fan will operate up to 1 billion rotations. andre lives in a hot climate, works outside of the home from approximately 8: 00 am to 5: 00 pm, monday through friday, does not own an air conditioner, and can't sleep with the fan running. estimate how many hot days n hot andre will be able to use the fan, rounded to the nearest day.

Explanation:

Total Minutes

The fan can achieve 1,000,000,000 rotations in its lifetime and does 700 rotations per minute

Therefore, the fan will work for = 1,428,571.45 minutes in its lifetime.

Working Time

Andre works for 9 hours, assuming he sleeps for 8 hours, The fan is on for 7 hours on weekdays (25 - 9 - 8), a total of 35 hours and

16 hours on the weekend (24 - 8), a total of 32 hours

The fan is on for 67 hours a week or 4020 minutes.

Downtime

Everyday the fan is used, it takes 5.0 seconds to get to its full speed and 7.0 seconds for the blade to stop, an additional 2 seconds per day. This adds 14 seconds per week.

In a week, the fan works for 4020 minutes + ()

=4020.23minutes

In its lifetime, the fan will work for weeks.

=355.35 weeks

OR 355.35 X 7 Days

2487 hot days

acceleration = (change in speed) / (time for the change)

change in speed = (20-120)= -100 m/s.

1.5 min = 90 sec

acceleration = -100/90 = -1.11 m/s^2.

we don't care about the 150kg or the 2,500 meters. they don't make any difference.

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