up a circular helical staircase around a silo of radius 25 ft. As the farmer
climbs, grain leaks from the sack at a rate of 1 lb per 10 ft of ascend.
How much work is performed by the farmer in climbing through a vertical
distance of 60 ft in exactly 4 revolutions?
更新1:
These are all the things I know about the question, hope the following helps: Work Done=∫c F∙dr==∫ F(x(t),y(t),z(t))∙r'(t),where F is the force field and r is the parametrization of the curve.
更新2:
In this question, the parametrization of r should be r(t)=(25cos2πt,25sin2πt,15t).(Right?) The main problem of this question is how to find the force field representation at (x,y,z)=F(x,y,z). If the representation of the force field can be found, the whole problem will be solved.
