Consider a force F=−xi^+yj^. The work done by this force in moving a particle from point A(1,0) to B(0,1) along the line segment is: (all quantities are in SI units)
(A)2
(B)21
(C)1✓ Correct
(D)23
Answer: (C)
Solution
The work is ∫F⋅ds=∫(−xdx+ydy), and because each force component depends only on its own coordinate the two pieces integrate separately. As x runs from 1 to 0, ∫10−xdx=21, and as y runs from 0 to 1, ∫01ydy=21. Their sum is 1 J.
JEE Main · 2020 · 09 Jan 2020 · Shift 1 · Single correct option