[填空题]
A car starts rolling 0ts9kxnkq 3v8fj ( wb9down a 1-i::7 d ptnkal+frw of)z2u8y(4f tz8pfn-4 hill (1-in-4 means that for each 4 m traveled along the road, the elevation +zd(fop2ff:nta)p8u: wt4ryfzk8 7l change is 1 m). How fast is it going when it reaches the bottom after traveling 55 m? (a) Ignore friction.
(b) Assume an effective coefficient of friction equal to 0.10.
