Force acting on a particale is `(2hat(i)+3hat(j))N`. Work done by this force is zero, when the particle is moved on the line `3y+kx=5`. Here value of k is `(`Work done `W=vec(F).vec(d))`

Options

A. 2
B. 4
C. 6
D. 8

Answer

A

Explanation

Given, `F=2hat(i)+3hat(j)`
displacement `ds=dx hat(i)+dyhat(j)+dz hat(k)`
work done, `w=int F.ds =int (2 dx+3dy)`
Also `3y+kx=5 implies (3dy)/(dx)+k=0`
`implies 3dy=-kdx implies W=int (2dx-kdx)=0`
`implies 2x=kx implies k=2`