A car travels 40kilometers at an average speed of 80 km/h and then travels 40 kilometers at an average speed of 40 km/h. The average speed of the car for this 80 km trip is? Why?
2006-06-19 16:48:20 · 14 answers · asked by WADEcounty 2 in Science & Mathematics ➔ Physics
53.3 km/hr
trip takes 1.5 hours so 80/1.5 gives you km/h.
2006-06-19 16:54:11 · answer #1 · answered by Toe_Breaker 2 · 3⤊ 3⤋
The first 40 km takes 30 minutes (40 km / 80 km/hr = 1/2 hr). The 2nd 40 km takes an hour (40 km / 40 km/hr = 1 hr)
Total time is 90 minutes to travel 80 km.
80 km / 90 min * 60 min / 1 hr = 53 1/3 km/hr.
2006-06-19 17:01:44 · answer #2 · answered by Raymond C 4 · 0⤊ 0⤋
You need to figure out how much total time the car was travelling:
In the first half of the trip the car travelled 40km/80km/hr = 1/2 hr
In the second half 40 km/ 40km/hr = 1 hr
So the car travelled 1.5 hrs total. 80 km/1.5 hrs = 53 1/3 km/hr
2006-06-19 17:16:27 · answer #3 · answered by James A 3 · 0⤊ 0⤋
1. Can I answer the physics problem? Yes.
It takes him 30 minutes to travel the first 40K. Then it takes him an hour to travel another 40K. So, he covers 80K in 1.5 hours. That makes his average speed 53 1/3 KPH.
2. Am I the smartest person in the world? No.
One to two percent of the people in the world are probably smarter -- putting me somewhere between the 60 millionth to 120 millionth smartest person in the world. Doesn't sound so impressive that way.
2006-06-19 16:57:19 · answer #4 · answered by Ranto 7 · 0⤊ 0⤋
Yes, No. 53.333km/h because the first leg took 30 minutes 40km/80km/h equals 1/2 hour and the second leg took 1 hr 40km/40km/h equals 1 hour. Total distance of trip is 80km divided by the time of trip of 1 1/2 hours equals 53.333km/h.
2006-06-19 17:10:52 · answer #5 · answered by wefields@swbell.net 3 · 0⤊ 0⤋
It went 40 kilometers one way and went back over the same 40 kilometers to the starting point.
2006-06-19 16:55:39 · answer #6 · answered by Retarded Dave 5 · 0⤊ 0⤋
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2016-10-14 08:01:46 · answer #7 · answered by ? 4 · 0⤊ 0⤋
average speed = (distance travelled)/(time taken)
distance travelled = 80 km
time = 1.5 hrs
so, average speed = 80/1.5= 53.33km/hr
2006-06-19 16:59:56 · answer #8 · answered by Great Advisor 2 · 0⤊ 0⤋
when his speed is 80:
v=s/t
80=40/t
t=0.5hour
when his speed is 40:
t=s/v
t=40/40
t=1hour
his average speed is :
v=s/t
v=(40+40)/(0.5+1)
v=80/(1.5)
v=53.33km/hour
2006-06-19 17:23:24 · answer #9 · answered by lkamh 2 · 0⤊ 0⤋
Google physics help or seek the help of a teacher.
2006-06-19 16:51:38 · answer #10 · answered by libbyocto14 2 · 0⤊ 0⤋
53.33333....
the 1st leg took him half an hr
the 2nd leg took him a full hr
total trip=1.5 hrs
80km/l.5hrs=53.333km/h
2006-06-19 16:58:40 · answer #11 · answered by bandido 4 · 0⤊ 0⤋