In: Physics
A spelunker is surveying a cave. He follows a passage that goes 179 m straight west, then 211 m in a direction 45° east of south, then 285 m at 30° east of north. After a fourth unmeasured displacement he finds himself back where he started. Use a scale drawing to determine the fourth displacement.
a) magnitude | _______ m |
b) direction |
_______° SELECT ONE -----> : (north of east) (south of east) (south of west) (north of west) |
vector X- component Y-component
179 m west - 179 0
211 m 45° east of south 211 Sin45 - 211 Cos45
285 m at 30° east of north 285 Sin30 285 Cos30
Net displacement in X-direction = -179 + 211 Sin45 + 285 Sin30 = 112.7 m
Net displacement in Y-direction = 0 - 211 Cos45 + 285 Cos30 = 97.6
so net fourth displacement = sqrt (112.72 + 97.62) = 149.1 m
=
tan-1 (Y/X) = tan-1(97.6/112.7) = 40.89 north
of east