6 polnts hrw10 3p017 go defective Three vectors a b and C ea
Solution
a)
a = 80*cos(20) i + 80*sin(20) j
b = 80*cos(190) i + 80*sin(190) j
c = 80*cos(280) i + 80*sin(280) j
So,
a + b + c = (80*cos(20) + 80*cos(190) + 80*cos(280)) i + (80*sin(20) + 80*sin(190) + 80*sin(280)) j
So,
a + b + c = 10.3 i - 65.3 j
So, magnitude = sqrt(10.3^2 + 65.3^2)
= 66.1 m <----------answer
b)
angle = - atan(65.3/10.3) = -81 deg = 279 deg
c)
a - b + c = (80*cos(20) - 80*cos(190) + 80*cos(280)) i + (80*sin(20) - 80*sin(190) + 80*sin(280))
So,
a - b + c = 167.9 i - 37.5 j
So, magnitude = sqrt(167.9^2 + 37.5^2)
= 172 m
d)
angle = 360 - atan(37.5/167.9) = 347.4 deg
e)
(a+ b) - (c+d) = 0
So, d = a+b-c
So, d = (80*cos(20 deg) + 80*cos(190 deg) - 80*cos(280 deg)) i + (80*sin(20 deg) - 80*sin(190 deg) - 80*sin(280 deg)) j
So, d = -17.5 i + 120 j
So, magnitude = sqrt(17.5^2 + 120^2)
= 121.3 m
f)
angle = 180 - atan(120/17.5) = 98.3 deg

