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May 5, 2016

# Homework Help: Trig/Physics

Posted by Nycw on Wednesday, July 18, 2012 at 10:01pm.

Joe walks 5 miles in the direction degrees North of East, and then 10 miles in the direction 20 degrees West of North.

(a) How far is Joe from his starting position?
(b) In what direction is Joe from his starting position?
• Trig/Physics - drwls, Wednesday, July 18, 2012 at 11:14pm

You left out an important number that is needed to compute the answer. It should follow the first word "direction". How many degrees is the first direction North of East?

• Trig/Physics - Nycw, Wednesday, July 18, 2012 at 11:38pm

Hi, sorry it was 30 degrees North of East.

• Trig/Physics - drwls, Thursday, July 19, 2012 at 1:18am

total displacement north
= 5 sin 30 + 10 cos20
= 2.5 + 9.397
= 11.897 miles

total displacement east
= 5 cos30 - 10 sin20
= 4.33 - 3.42
= 0.91 miles

(a) sqrt[(11.897)^2 + (0.91)^2]
= 11.93 miles
(b) direction = tan^-1 0.91/11.897
E of N
= 4.37 deg E of N

• Trig/Physics - Nycw, Thursday, July 19, 2012 at 3:50am

Hi, thank you so much. Everything I tried hit all around the borders, but just was not working out correctly. I really appreciate your help.