Question

A particle moves from a point `vec (r)_(2)=(2hat(i) +3hat(j))` to another point `vec (r)_(2)=(3hat(i) +2hat(j))` during which a certain force `vec(F)=(5hat(i)+5hat(j))` acts on it. Calculate work done by the force on the particle during this displacement.

Answer 1

Here,`vec(r)_(1)=(2hat(i)+3hat(j)) ` and `vec(r)_(2)=(3hat(i)+2hat(j))`
`vec(F)=(5hat(i)+5hat(j)), W=?`
Displacement, `vec(s)=vec(r)_(2)-vec(r)_(1)=(hat(i)-hat(j))`
`W=vec(F).vec(s)=(5hat(i)+5hat(j)).(hat(i)-hat(j))=5-5=0`