ENGR 1990 Engineering Mathematics
Lab/Recitation #8 – 2D Vectors and Solving Simultaneous Equations
1. A weight of 500 (lb.) is supported by the two wires as shown.
acting at point A to zero   F  0  , complete the following.
By setting the sum of the forces
a) Find the two equations that must be solved to find the magnitudes of the forces FAB and FAC .
b) Solve the two simultaneous equations using the methods of substitution and Cramer’s rule.
C
B
5
3
4
5
3
A
4
A
W
Free Body Diagram (FBD)
2. For the double-loop DC circuit shown, the currents I1 and I 2 can be found by solving the following
simultaneous equations.
 R1  R3  I1   R3  I 2  V1
 R3  I1   R2  R3  I 2  V2
Given the resistances R1  5() , R2  6 () , and R3  10 () , and the voltages V1  24 (volts) , and
V2  6 (volts) , find the currents I1 and I 2 using substitution and matrix inversion.
1/1