A man moves 6.0m East and then 10.0m N30ºE. How far is he from his starting point?
A
15.0m
B
17.0m
C
14.0m
D
12.0m
Verified Correct Answer: C.
Physical Principles & Numerical Solution
The two displacements are 6.0 m East and 10.0 m at N30ºE.
The angle between East and N30ºE is 60^\circ.
Using the cosine rule:
R\(^2\) = 6\(^2\) +10\(^2\) +2(6)(10)cos60º
R\(^2\) = 36 + 100 +120 (0.5) = 196
R = \(\sqrt{196}\) = 14.0m
Source: Myschool Past Questions Archive (Record #74349)