29. Motion in the plane The coordinates of a particle in the metric xy-plane are differentiable functions of time / with dx/di = -1 m/sec and dy/dr = -5 m/sec. How fast is the particle's dis- tance from the origin changing as it passes through the point (5, 12)? 30. A moving shadow A man 6 ft tall walks at the rate of 5 fit/sec toward a streetlight that is 16 ft above the ground. At what rate is the tip of his shadow moving? At what rate is the length of his shadow changing when he is 10 ft from the base of the light