[填空题]
The coefficient of s9 ;wzkgq x, 9*8pfdwib/g/3m mduk)tqtatic friction between haaomtoi6x.4: seg+p+ grd rubber and normal street pavement is about:+to 4iam.seg6g+o xp 0.8. On how steep a hill (maximum angle) can you leave a car parked? $^{/circ}$
