(a) Explain why the stability of a person against a toppling force is increased by spreading the legs as shown in the figure.
(b) Calculate the force required to topple a person of mass m=70 kg, the height of shoulder h=1.4m, standing with his feet spread d=0.9 m apart as shown in the figure. Assume the person does not slide and the weight of the person is equally distributed on both feet.