[填空题]
The coefficient of static friction 3lbftcbv hc /5 b;jv6aqmn +kt8*x+/bbetween hard rubber 8cqub )ela 9ify on;v9u2p.w- ep-d5v and normal street pavement is about 0.8. On how steep a hill (maximum and8fpei)qbo -ve 2 cuyl;9-5uawn9v.pgle) can you leave a car parked? $^{/circ}$
