Answer:
6.0
Explanation:
Given two collinear vectors A and B, if the vectors are added, the resultant will have a magnitude of 4.0. This can be expressed as;
A+B = 4...(1)
Similarly, if the vector difference has a resultant magnitude of 8.0, this can be expressed as;
A-B = 8...(2)
Solving equation 1 and 2 simultaneously;
A+B = 4... (1)
A-B = 8... (2)
Adding equation 2 to 1, the resulting equation will give;
A+A = 4+8 (note that B will cancel out)
2A = 12
A = 6.0
Therefore the magnitude of A is 6.0
