A 44 kg woman leaps vertically from a crouching position in which her center of mass is 48 cm above the ground. As her feet leave the floor her center of mass is 81 cm above the ground; it raises to 124 cm at the top of her leap. What average force was exerted on her by the ground during the jump? the initial force is the normal force (44 * 9.81) = 431.64 N but i don't know what the final force is. after i find the final force the average is (Fi+Ff)/2.