- #1

PhysicsBoyMan

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## Homework Statement

A person takes a trip, driving with a constant speed of 89.5 km/h, except for a 22-min rest stop. If the person's average speed is 77.8 km/h

a) How much time is spent on the trip?

b) How far does the person travel?

## Homework Equations

v1 = 89.5 km/h -> t

v2 = 0 km/h -> 0.37 h

AvgV = 77.8 km/h

a = 0 since speed is constant

## The Attempt at a Solution

I have been given formulas throughout my textbook to solve for displacement, velocity, acceleration, and things like this. I will try to briefly show the kind of problems I run into and my thought process in solving this:

I'm looking for x (distance) and t (time) anywhere I can make it work basically.

average v = Δx / Δt I don't have Δx so I can't use this to find t.

v = vo + at I have original velocity but I can't isolate time because a=0.

All of my other equations don't work because they divide by 0, there are 2 unknown variables, or other such problems.

Im starting to wonder about how my "t"s are split into 2 parts in my question (0.37h and unknown) but in my equations there is only one variable t. I don't think my equations will work.

I can average the two velocities out to 89.5 km/h, but I can't figure out how to account for times which would make one velocity count for more than the other.

I tried to input 1h for my unknown t and calculate average velocity just to see if that would help me better understand the problem. I still don't know how to calculate average velocity without x (displacement). And I don't know how to find x with two different time values. I am really stuck!