Question #4dd1c

2 Answers

Answer:

c

Explanation:

Draw 2 triangles from the vectors
vector a is 12m @ 40 degrees
vector b is 9m @ 20 degrees

Any line that's not straight can be a hypotnuse.
Based on the graph, you need cosine to find x since cos=hyp/adj and adj is moving in the x axis.

#costheta=(adj)/(hyp)# ---> #hypcostheta=opp#

Vector a: #a=12cos40=9.19#
Vector b: #b=9cos20=8.46#

a goes in the positive direction and b goes in the negative direction, so #9.19-8.46=.735# which is basically c

Mar 27, 2017

As given in the question

#veca# subtends #40^@# angle with +ve direction of X-axis and #absveca=12m#

#vecb# subtends #(180-20)^@=160^@# angle with +ve direction of X-axis and #absvecb=9m#

So the component of #veca+vecb# along X-axis will have magnitude

#=absvecacos40^@+absvecbcos160^@#

#=(12cos40^@+9cos160^@)m~~0.73m#