Question

(A). Calculate the impulse imparted to a 70-kg person landing on a firm ground after jumping from a height of 5.0 m. Then estimate the average force exerted on the person's leg if the landing is (b) stiff-legged and (c) with bent legs. in (b) assume the center of mass of the body moves 1.0 cm during impact and in (c), about 50 cm.

Answer 1

Giren data :- m-70kg hosom (a velocity (w of the man is va Jagh. V= √2(9.805) V= 9.89 m/s. Impulse I m (v-u). [eo]. I- 70 (9.89-0) I= 692.96 kgm/s/ (6) when a person's feet touch the ground body moves Icom is w.kil vru - Das [:ce=0]. BREV a- (9.8979 – 4891 m/s. 2(0.01) Now force & -matg). F=70 (4891 +9.81) TF = 343056.7N. (c) when a peyson's feet touch the ground in the bent condition body moves 50cm is sa = 2as → a= v A= (9.89) 25 260.05) = 97.81 m/s force: f= m(atg) = 70 (97.849.81) = 7533.5 N/