Answer to number 8 please

Acceleration = (change in speed) / (time for the change)(Note:  That's all the Physics there is to this problem. The rest is all arithmetic.)=======================================change in speed = (40 - 20) miles/hour = -20 miles/hourtime for the change = 10 minutesAcceleration =  (-20 miles/hour) / (10 minutes) =                          -2 miles/hour per minute .That's a perfectly good and technically correct expression for acceleration.But obviously the units might make some people dizzy.  So let's try toclean it up a little. Notice that 10 minutes is 1/6 of an hour.So we could write the acceleration asAcceleration = (-20 miles/hour) / (1/6 hour) = -120 miles/hour per hour =                         -120 miles/hour² .You could convert this into any units you like.  It's really not a physics problem any more, it's just an exercise in converting units.

First segment: The airplane is descending slowly, with time and distance at a 3:1 ratio. It is probably approaching the airportSecond segment: The airplane is maintaining its altitude. It is probably waiting for the other planes to clear awayThird segment:The airplane descending rapidly, with time and distance at a 1:2 ratio. It is probably landingSorry, my bad.To find acceleration, we use v2-v1 /t40mph - 20mph / 10 min20mph/10minWe can convert this to 20/6 miles per 10 minutes, and cancel out the 10 min to 20/6 miles, which is 10/3 miles