Answer: 15Nm
Explanation:
Work is said to be done when a force cause a body to move through a distance. Mathematically,
Work = Force (F) × distance (s)
If F = F~ = (3 N)ˆı + (−1 N) ˆj + (7 N) ˆk
S = (5 m)ˆı + (3 m) ˆ + (−4 m) ˆk
According to vector notation,
i.I = j.j =k.k = 1
Multiplication of different component will give 'zero'
F×s = (3 N)ˆi × (5 m)ˆı
Work done = 15Nm