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 16:47:17 · 12 answers · asked by WADEcounty 2 in Science & Mathematics ➔ Physics
The first speed comes to 40 km in 30 minutes. The second speed comes to 40 km in 60 minutes. The total trip is 80 km in 90 minutes. The average speed is 80km/1.5 hrs. The average speed is 53.33km/hr. This is because it is traveling fast for a short time and traveling slow for a long time. Intuitively, you would think 60km/hr (which I did when I first read it), but if you check the math, that's not possible.
2006-06-19 16:55:10 · answer #1 · answered by matticus finch 2 · 0⤊ 1⤋
Add 40 + 80 = 120 divide this number by 2 (because the trip is divided into 2 parts 40kilos at 80km/h and 40kilos at 40km/h) you get 60. this is the average speed of the car and also helps you answer the question of how long the total trip took in time. 1 hour 33 minutes and 33 seconds.
2006-06-19 16:58:12 · answer #2 · answered by jafnarf 3 · 0⤊ 0⤋
40 km + 40 km = 80 km the total distance traveled.
doing 80kmh half of the total distance and 40kmh for the other half would infer an average of 60km/h. You simply split the differance between 80 and 40.
2006-06-19 16:57:07 · answer #3 · answered by Anonymous · 0⤊ 0⤋
The average speed is not 60. It is calculated by first finding the time taken for the 2 trips separately. Now divide the total distance by the total time to get 80/1 +0.5
2006-06-19 17:58:27 · answer #4 · answered by naina s 1 · 0⤊ 0⤋
Total distance: 40 km + 40 km
Total time: .5 hr + 1 hr
Speed = 80 km / 1.5 hrs = 53.33 km / hr
2006-06-19 16:56:35 · answer #5 · answered by Anonymous · 0⤊ 0⤋
the ave speed is 60 isnt it? because half of the journey is 40 km and you average the two average speeds. and no im not the smartest but i did pass physics.
2006-06-19 16:51:57 · answer #6 · answered by K8 2 · 0⤊ 0⤋
60 km/hr.
(40 + 80)/2 = 60
2006-06-19 16:50:59 · answer #7 · answered by Levi E 3 · 0⤊ 0⤋
Yes, maybe, 60km/h, and that would be because half of the distance was driven at 80km/h while the other half was at 40km/h -- therefore, (80+40)/2 is the correct answer: 60.
2006-06-19 16:55:14 · answer #8 · answered by Anonymous · 0⤊ 0⤋
the first 40 km takes 0.5-hour (40 km / eighty km/hr = a million/2 hr). The 2d 40 km takes an hour (40 km / 40 km/hr = a million hr) entire time is ninety minutes to commute eighty km. eighty km / ninety min * 60 min / a million hr = fifty 3 a million/3 km/hr.
2016-10-14 08:01:44 · answer #9 · answered by ? 4 · 0⤊ 0⤋
53.33 km/h
First trip is half an hour. Second trip is one hour. Total duration is 1.5 hours for an 80 km trip. 80/1.5=53.333
2006-06-19 17:03:44 · answer #10 · answered by 1ton 1 · 1⤊ 0⤋