[填空题]
A car starts rollingl 7vr1khmh;c4 7tk5a7.oa9/id xgcx j down a 1-in-4 hill (1-in-4 mezw zr 1xh c418t/hln7tans that for each 4 m traveled along the road, the elevation change is 1 m). How fast is it going wh hz8ch1w7 tn/rx 1lt4zen it reaches the bottom after traveling 55 m? (a) Ignore friction.
(b) Assume an effective coefficient of friction equal to 0.10.
