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May 6, 2016

# Homework Help: Physics

Posted by Bridge on Saturday, September 17, 2011 at 8:10pm.

A rescue plane wants to drop supplies to isolated mountain climbers on a rocky ridge 235 m below. Assume the plane is traveling horizontally with a speed of 195 km/h (54.2 m/s).
Suppose, instead, that the plane releases the supplies a horizontal distance of 425 m in advance of the mountain climbers. What vertical velocity (up or down) should the supplies be given so that they arrive precisely at the climbers' position (assume up is positive).
With what speed do the supplies land in the latter case?
• Physics - Damon, Saturday, September 17, 2011 at 8:28pm

425 = 54.2 t
t = 7.84 seconds in air

h = ho + Vi t - 4.9 t^2
-235 = Vi (7.84) - 4.9 (7.84)^2
-235 = 7.84 Vi - 301
Vi = 8.45 m/s up
------------------------------
Horizontal speed = 54.2 always
find vertical speed at rocks
v = Vi - g t
v = 8.45 - 9.8 (7.84)
v = -68.4
so speed = sqrt (54.2^2 + 68.4^2)

• Physics - Anonymous, Wednesday, October 14, 2015 at 10:39pm

kj