A skier weighing 600 N goes over a frictionless circular hill of radius R 20 m that the effects of air resistance on the skier are negligible. As she comes up the hill, her speed is 8,0 \( \mathrm{m} / \mathrm{s} \) at point \( B \), at angle \( \theta=20^{\circ} \). (a) What is her speed at the hilltop (point \( A \) ) if she coasts without using her poles? (b) What minimum speed can she have at B and still coast to the hilltop? (c) Do the answers to these two questions increase, decrease, or remain the same if the skier weighs 700 N instead of 600 N ?