If these components project by more than 9 75 mm from the surface of the instrument panel, they shall be so designed and constructed as to be able, under the effect of a longitudinal horizontal force of 37.8 daN delivered by a flat ended ram of not more than 50 mm diameter either to retract into the surface of the panel until they do not project by more than 9 75 mm or to become detached; in the latter case no dangerous projections of more than 9 75 mm shall remain; a cross-section not more than 6 75 mm from the point of maximum projection shall be not less than 6 750 cm2 in area.