汽车从甲地到乙地速度为ν 1 =30km⼀h,回来时速度为ν 2 =45km⼀h,且甲乙两地相距s=180km,求:(1)汽车

2025-05-14 04:54:58
推荐回答(1个)
回答1:


(1)∵S=180km,ν 1 =30km/h,
∴t 1 =
S
v 1
=
180km
30km/h
=6h,
又∵ν 2 =45km/h,
∴t 2 =
S
v 2
=
180km
45km/h
=4h,
所以汽车来回一次所用时间为:t=t 1 +t 2 =6h+4h=10h.
答:汽车来回一次所用时间为10h.
 (2)∵S =2S=2×180km=360km,t=10h,
.
v
=
S
t
=
360km
10h
=36km/h.
答:汽车来回一次的平均速度为36km/h.