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Exercise 1214Calculus › Multivariable calculus › Vector calculusL1Added 3 Nov 2026

Work done by a force field

#work#line integral#vector field

Statement

Compute the work of F⃗(x,y)=(y,x)\vec F(x,y)=(y,x) along the segment from (0,0)(0,0) to (1,2)(1,2).

Hint

Work =∫CF⃗⋅dr⃗=\int_C\vec F\cdot d\vec r. Parametrize γ(t)=(t,2t)\gamma(t)=(t,2t).

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Solution

Parametrization. γ(t)=(t,2t)\gamma(t)=(t,2t), γ′(t)=(1,2)\gamma'(t)=(1,2), t∈[0,1]t\in[0,1].

Integrand. F⃗(γ(t))=(2t,t)\vec F(\gamma(t))=(2t,t), F⃗⋅γ′=2t+2t=4t\vec F\cdot\gamma'=2t+2t=4t.

Integral. ∫014t dt=2\int_0^1 4t\,dt=2.

Conclusion. Work =2=2.