抄録
Imporvements were added to the experimental apparatus used before so as to take the simultaneous measurements of the horizontal and vertical components of the resistive force acting upon a wheel rolling on sand dried in natural state and also the depth of the sinking of the wheel in sand. The range of measurement was widened at the same time.
By the use of this renewed apparatus, variations of the constants K and n of the empirical formula H=KVn, which relates the horizontal components H to the vertical components, V of the resistive force acting upon a disc-shaped wheel, were measured under different conditions in regard to the diameter and the thickness of the wheel and the packing state of the sand. The results obtained are applied to the study of the relationship between the traction resistance of a car and the position of its gravity center.
