对坐标的曲线积分
概念与性质
概念
例题:若质点在变力 $F=(-yz,xz,z)$ 的作用下,沿着螺旋线 $\Gamma: x = 2cost, y = 2sint, z = t$ 从点 $M(2,0,0)$ 运动到点$N(-2,0,\pi)$ ,则变力做的功 $W = $
$W = \int_\Gamma -yzdx+xzdy+zdz = \int_0^\pi(4tsin^2t+4tcos^2t+t)dt = \frac{5}{2}\pi^2$
例题:若质点在变力 $F=(-yz,xz,z)$ 的作用下,沿着螺旋线 $\Gamma: x = 2cost, y = 2sint, z = t$ 从点 $M(2,0,0)$ 运动到点$N(-2,0,\pi)$ ,则变力做的功 $W = $
$W = \int_\Gamma -yzdx+xzdy+zdz = \int_0^\pi(4tsin^2t+4tcos^2t+t)dt = \frac{5}{2}\pi^2$