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Catchingupquickly
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Homework Statement
A pilot is attempting to deliver emergency food and first-aid supplies to an isolated northern community that has suffered severe flooding. The plane has a horizontal velocity of 1.4 10^2 km/h as it flies at an altitude of 1.80 m x 10^2. The community is situated on a dry patch of land that is about 72m x 72m.
a) If the supplies are released just as the plane flies directly overhead, will they touch down on land or in the water? Justify your response with calculations that show exactly where the package will land.
b) When should the supplies be released so that they touch down very close to the centre of the dry patch of land? Answer in terms of distance from the target, not time.
Homework Equations
## \Delta \vec d_v = \frac 1 2 \vec a \Delta t^2#### \Delta \vec d_h = \vec v_h \Delta t##
The Attempt at a Solution
[/B]
Plane is flying at 1.4 x 10^2 km/h = 140 km/h or 38.8 m/s (140km/h x 1000m /3600s)
Altitude is 1.8 x 10^2 meters = 180 meters.
How long until it hits the ground
## \Delta \vec d_v = \frac 1 2 \vec a \Delta t^2##
## 180m [down] = \frac 1 2 (-9.8 m/s^2 [down]) (\Delta t^2
\\ \Delta t = {\sqrt {\frac {180m} {4.9 m/s^2}}}
\\ \Delta t = 6.1 seconds##
Horizontal distance travelled
## \Delta \vec d_h = (38.8m/s [fwd]) (6.1s)
\\ ≈ 237 m##
Where's it going to hit?
72m x 72m = 5184 m
So if released directly overhead that's half-way
5184/2 = 2592 m
So it's going to drift another 237m [forward] therefore it will land at 2592 + 237 = 2829m
b) To release it so it hits dead centre, release at 2592 - 237 or at the 2355th meter.
Critique, feedback, and/or verbal abuse welcomed.