Question

Question #4dd1c

Answer 1

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

Answer 2

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`