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wbetting
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Homework Statement
A plane flies 425 km east from city A to city B in 40.0 min and then 954 km south from city B to city C in 1.70 h. For the total trip, what are the (a) magnitude (in km) and (b) direction of the plane's displacement, the (c) magnitude (in km/h) and (d) direction of its average velocity, and (e) its average speed (in km/h)? Give your angles as positive or negative values of magnitude less than 180 degrees, measured from the +x direction (east).
Homework Equations
magnitude is sqrt of a^2+b^2
direction is tan inverse of ay/ax
The Attempt at a Solution
ok so i found magnitude and direction and got parts a and b, c,e right but got part d, wrong and i think its because of a mathematical mistake but its driving me nuts! i got 1044.39 km for a and -65.987 degrees for b. for c i found velocity avg for x and y for avg velocity of x i did (425km/.666hr)= 637.5 km/h
for avg velocity y i did (954km/1.7 hr)= 384.71 km/hr
for d i did sqrt 637^2+384.71^2= 434.33 km/hr
i can't figure out what i did wrong on d i did inverse tan of -434.33/637.5 and keep getting -34.26 and at one point got -31.11. whattt am i doing wrong?!