Help with vectors?

Question

Vector A has x and y components of -20 cm and 12 cm, respectively; vector B has x and y components of 4.79 cm and -20 cm, respectively.

a - If A-B+3C=0, what is the x component of C? Answer in units of cm.

b - What is the y component of C? Answer in units of cm.


I got Cx to be -15.21cm and Cy as -8...but bringing it back that equation doesnt equal 0..unless I did something wrong.

Answer 1

You must, must you not? Very well indeed...

A= -20i + 12j
B= 4.79i - 20j

F=A - B + 3C=0 means Fx and Fy are 0.

We have
Fx=-20i - 4.79i +3Cx=0
Cx= (24.79)/3= 8.26 cm

Same treatment is given to find Cy
Fy=Ay - By + 3Cy=0
12 -(-20)+3Cy=0
Cy=32/3=10.7cm