[填空题]
(a) What is the acceleration of two f :sf d(r(c1oddalling sky dix8u+kv )sllpa5zejgs td +0 e0d53az(vers (mass 132 kg including parachute) when the upward force of air resistance is equal to onaa (xd0 pe0)+e3zl+8 lstkv duj55 zgse-fourth of their weight?
(b) After popping open the parachute, the divers descend leisurely to the ground at constant speed. What now is the force of air resistance on the sky divers and their parachute? See Fig. 4–39.
