I Am Studing For The At-sat Test And I Ran In To This Question On The Pre-test. Can Anyone Figure This Out?
If a plane was decending at 500 feet per second from an attitude of 18,000 feet traveling at 165MPH, how many miles would the plane have to traveled as it decended to 14,500 feet? (Air Traffic Control Career Prep)
A. 25
B. 19
C. 12
D. 30
According to the book the answer is B. 19
EDIT: err.. I’m guessing the book meant 500 feet per minute.. 500 feet per second would be too fast of a descent
It descends 3500 feet, which takes 7 minutes.
7 minutes in hours is 7/60.
Distance = Time * Rate
(7/60 hours) * (165mph) = 19.25, rounded to 19 miles.
well if it is descending to 14500 then it has descended 3500 feet. at 500feet/sec it will take 7 secs to go down that far.
165mph is 0.045 833 333 333 miles per sec so 0.045 833 333 333 x 7=0.320833333331
then imagine it as a right angle triangle with 3500 as the vertical side and the 0.320833333331 as the horizontal side.
we now need to work out the hypotenuse as the distance travelled. so:
as we know: a^2+b^2=c^2
so: 0.320833333331^2+3500^2=c^2
so: c=1,118.034034
so basically i have no idea =D
sorry
Doesn’t sound right to me –
18000 – 14500 = 3500 feet
@ 500 feet per second that is 3500 / 500 = 7 seconds
165 miles/hour ( 7 seconds) ( 1 hour / 3600 seconds) = 0.3208 miles traveled
———————-
If the answer is 19 miles – that would take 6.9 minutes to fly at 165 MPH. At 500 feet per second for 6.9 minutes you would decend 207,000 feet.
18,00 ft to 14,500 ft = 18,000 – 14,500 = 3,500 ft
3,500 ft at 500 ft per sec. 3500 / 500 = 7 sec
7 sec at 165 mph
165 mph / 60 = 2.75 miles per min
2.75 miles per min / 60 sec = .045833… miles per sec.
.045833 X 7 sec = .32 miles. I think you wrote the question down wrong. ( or the book is wrong)
It took (18000 -14500) / 500 = 7 seconds to descend
In 7 seconds, it traveled 165 * (7/3600) = ?
Oh! You don’t get the answer. But if the problem is changed to descending at 500 ft per minute, you get it as
165 * (7/60) = 19 miles
Time the plane takes to decent to 14500 is
(18000-14500)/500 = 7 sec
Distance trave by plane in 7sec
165 * 7 / 3600 = 0.32
But 165 * 7 / 60 = 19.2
so either the equation is 500 feet per min or none of the answer is correct.
yeah i came across the same problem. the book is wrong. when they say sec they mean min