A bus started out going 20 miles per hour on the highway. One hour later it drove 40 miles per hour on the freeway. How long did it take to go 140 miles?
acceleartion= (40-20)/60 min
d= vi*t+1/2 at
140=20*t+1/2(20/60)t^2 solve for t, in minutes.
To determine how long it took for the bus to travel 140 miles, we need to consider the different speeds at which it traveled on the highway and the freeway.
Let's break down the journey into two parts:
1. The bus traveled at 20 miles per hour on the highway for a certain amount of time.
2. After one hour, the bus increased its speed to 40 miles per hour on the freeway for another portion of the journey.
First, let's find out how long it took for the bus to cover the distance on the highway:
Distance = Speed × Time
To find the time, we rearrange the equation:
Time = Distance / Speed
On the highway, the speed was 20 miles per hour. Let's denote the time taken on the highway as t1:
t1 = Distance / Speed
t1 = Distance / 20
Next, we need to calculate the time spent on the freeway after one hour of driving at 40 miles per hour. The total time for this leg of the journey is one hour less than the total time for the entire journey:
t2 = Total Time - 1
Finally, we can determine the total time for the journey by adding the times on the highway and the freeway:
Total Time = t1 + t2
We are given that the total distance traveled was 140 miles. Substituting this value into the equation, we get:
t1 + t2 = 140
Now, let's substitute the values we have derived into this equation and solve for t1 and t2.