Sunday
April 20, 2014

# Homework Help: physics

Posted by Julio on Thursday, August 9, 2012 at 6:32pm.

A plane leaves Seattle, flies 84.0{\rm mi} at 21.0^\circ north of east, and then changes direction to 52.0^\circ south of east. After flying at 120{\rm mi} in this new direction, the pilot must make an emergency landing on a field. The Seattle airport facility dispatches a rescue crew.

In what direction should the crew fly to go directly to the field? Use components to solve this problem.

How far should the crew fly to go directly to the field? Use components to solve this problem.

• physics - Henry, Friday, August 10, 2012 at 12:37pm

D = 84mi @ 21Deg. + 120mi @ -52Deg.

X = 84*cos21 + 120*cos(-52) = 152.3 Mi.
Y = 84*sin21 + 120*sin(-52) = -64.5 Mi.

tanA = Y/X = -64.5 / 152.3 = -.042343.
A = -22.9 Deg. = 22.9 Deg. S. of East.

D=X/cosA = 152.3 / cos(-22.9)=165.3 Mi.
= Dist.

• physics - Elena, Friday, August 10, 2012 at 12:57pm

a=84 mi, b=120 mi c=?

a•cos21+b•cos 55 = c•cosθ
b•sin55-a•sin21= c•sinθ
c•cosθ =84• •cos21+120•cos 55 =146.5 ...(1)
c•sinθ = 120•sin55-84•sin21 = 68.16 ...(2)
Divide (2) by (1)
tanθ =68.16/146.5 = 0.465
θ =arctan0.465 = 24.95º (south of east)

From (1)
c=146.5/cos24.95 = 161.6 mi

• physics - Elena, Friday, August 10, 2012 at 12:59pm

My mistake: I've used 55 instead of 52

Related Questions

Physics - A plane leaves Seattle, flies 84.0 at 21.0 north of east, and then ...
physics - A plane leaves Seattle, flies 77.0 mi at 22.0 degrees north of east, ...
Chem104 - Calculate the specific heat $$(\rm{J/g \; ^\circ C})$$ for a 18.5-\(\...
chemistry - Calculate the specific heat (\rm{J/g \; ^\circ C}) for a 18.5-\rm g ...
chem - Calculate the specific heat (\rm{J/g \; ^\circ C}) for a 18.5-\rm g ...
physics - A plane leaves Seattle, flies 85 mi at 22 degrees north of east, and ...
chemistry - assuming complete dissociation of the solute, how many grams of \rm ...
chemistry - How many grams of water can be cooled from 35^\circ {\rm C} to 16^\...
chemistry - 25.6 {\rm mL} of ethanol (density =0.789 {\rm g}/{\rm mL}) initially...
chemistry - Calculate the amount of heat required to heat a 3.6{\rm kg} gold bar...

Search
Members